Fourth Doctor

Filled with wanderlust and a renewed curiosity towards exploring time and space, the Fourth Doctor left all ties of his previous incarnation's exile behind on Earth, setting off to travel the universe, taking advantage of his freedom once more.

This incarnation of the Doctor initially travelled with Sarah Jane Smith and Harry Sullivan, but Harry chose to remain on Earth when the opportunity arose. The Doctor and Sarah continued on their adventures until the Doctor was summoned to Gallifrey, necessitating that he leave Sarah Jane behind as humans were not allowed on Gallifrey at the time.

After tangling with the Master on Gallifrey when he tried to heal himself and renew his regeneration cycle, he met and travelled with Leela of the Sevateem. During his travels with Leela, the Doctor gained a new companion in the robot dog, K9. Returning once more to Gallifrey to stop an invasion of Vardans, Leela and the original K9 stayed behind there.

On the White Guardian's orders, the Doctor began looking for the Key to Time with fellow Time Lady Romana and K9 Mark II. Once that search was concluded, the Doctor and Romana went on the run from the Black Guardian. Not long after, Romana regenerated into a new body and continued to travel with the Doctor and K9. Romana was later called back to Gallifrey, and the Doctor would meet Felicity Thomson on the Space-Whale. Together, the two would encounter the Terileptils, the Mara and ultimately, both the Master and the Psychrons. They would defeat the two foes, but only at the cost of the Doctor's life. The Doctor would say his goodbyes to Felicity, and allow a blue glow to envelop him and replace him with his next incarnation.

Post Regeneration
The Third Doctor's death took place ten years after the radiation from the Great One's lair caused severe damage to his body. (TV: Love and War) He returned to Earth to end his time in the company of Sarah Jane and the Brigadier. K'anpo Rimpoche soon arrived and kick started the regeneration. (TV: Planet of the Spiders)

Once he had regenerated, the Doctor suffered delirium, mumbling random things from his past adventures, and was physically exhausted. He was put in sickbay, where medical officer Harry Sullivan kept watch on him. However, the Doctor managed to outwit him and get to his TARDIS to leave. (TV: Robot)

Slipping away from UNIT HQ, the Doctor visited a planet colonised by the Mordee expedition, and encountered the colony ship's powerful computer, Xoanon, which he repaired from damage Xoanon sustained, accidentally imprinted his own mind on the computer, leaving him with multiple personalities. (TV: The Face of Evil)

Returning to UNIT HQ, though still with situational awareness issues, the Doctor was asked by the Brigadier to help deal with the Think Tank and their K1 robot, which had gone insane from so many contradictory orders its programming should have prevented it from doing. Afterwards, he returned to travelling in his TARDIS, taking Sarah Jane and Harry with him, abandoning a UNIT dinner party at Buckingham Palace and leaving without telling the Brigadier. (TV: Robot)

The Nerva Beacon
Due to Harry's inadvertent interference with the helmic regulator, the TARDIS landed on Space Station Nerva, where humanity had been cryogenically suspended to await Earth's recovery from solar flares. There, the Wirrn wished to use the humans as food and incubators for their kind after the human race had destroyed their breeding colonies throughout the Andromeda galaxy in a thousand-year battle with them, sending them into space. Unable to reproduce without terrestrial colonies, they sent their queen to the Nerva Beacon, who birthed several larvae before she died from the Nerva Beacon auto-guard. The larvae began to feast on humans, absorbing their knowledge and their bodies. Luckily, Noah, a human was converted into a Wirrn, retained his strong will and tricked the Wirrn into a suicide. Afterwards, on behalf of the space station, the Doctor went down to Earth with Harry and Sarah Jane to fix the transmat relay, leaving the TARDIS on the station, while Vira, the station's first medtech, tended to waking the rest of her crew from their long sleep. (TV: The Ark in Space)

Once on Earth, they found the Sontaran Styre conducting experiments on humans as a prelude to an invasion. Caught in the wrong place at the wrong time, the Doctor was accused of murdering a GalSec officer among a crew who had been lured to the Earth and slowly picked off by Styre. After escaping them, he rescued Sarah from an experiment where her inner fears were used against her. Styre appeared to fatally shoot the Doctor as he fled, but the Doctor had nicked a piece of the Nerva's synestic locking system, which guarded him from injury.

Knowing a Sontaran would not refuse an opportunity to engage in mortal combat, the Doctor returned and challenged Styre to a duel. This wore him out and bought Harry enough time to remove a terullian diode bypass transformer from the ship that nurtured Styre with energy, making the energy feed on Styre instead. The Doctor went on to address the Marshal who had sent Styre to Earth. The Doctor defeated his plans by bluffing the Marshal to call off his attack, allowing the resettlement of Earth to proceed, and transmatted with his companions back to the space station to retrieve the TARDIS. (TV: The Sontaran Experiment)

Intercepting their transmat beam, a Time Lord messenger appeared to the Doctor and forced him to undertake a mission on the Time Lords' behalf: prevent the creation of the Daleks or induce them to develop into less aggressive creatures. The messenger also gave the Doctor a Time Ring, which he could use to get back to his TARDIS. Upon their arrival on Skaro, the Doctor, Sarah Jane and Harry was caught up in a war between the Kaleds and Thals, with the Doctor being taken prisoner by the Kaleds with Harry after being separated from Sarah Jane. While being questioned, the Doctor met the creator of the Daleks, a scientist named Davros, attempting to genetically engineer the Kaleds as the effects of their weapons caused them to mutate, seeking to evolve their mutations into a perfect form. Despite respecting each other as scientists, the Doctor was unable to convince Davros to change the Daleks into better creatures.

When he revealed he knew of several defeats of the Daleks in the future due to faults in their design, the Doctor was forced to tell Davros of each failure the Daleks suffered, so that he could prevent them. Attempting to gauge the extent of his insanity, the Doctor posed a question to Davros, asking him what he would do if he possessed the power to end all other life. Davros's willingness to utilise such power horrified the Doctor, tempting him to cut off his life supports as a last resort of stopping his plans, but he was prevented from doing so by Nyder, and he was imprisoned. Escaping, the Doctor destroyed Davros' recording of the foreknowledge, thus keeping the future from changing for the worse.

The Doctor found little other option left than to ensure the Daleks would never exist, and had the opportunity to blow up the stock of embryonic Daleks that Davros had produced. However, he questioned if he had the right to destroy the Daleks, knowing that wiping out an entire species would make him just like them, and the fear of the Dalek had caused many worlds to ally with each other. With this in mind, the Doctor allowed the Dalek species to persist, and chose to stall their rise to power instead. Failing to listen to the Doctor's warnings, Davros found his own creations usurping him. Because they were programmed to acknowledge any creature as inferior to the Dalek, they deemed him unworthy to rule them. Fleeing after the Daleks killed Davros, the Doctor buried them and their factory underground, delaying their progression by a thousand years. (TV: Genesis of the Daleks)

The Doctor, Harry, and Sarah Jane returned to the Space Station Nerva earlier in its time line, when it orbited Jupiter, which had a fifty-year assignment to guide space freighters. The TARDIS was travelling back through time to them, leaving them stranded until it arrived. While waiting for it to arrive, the Doctor became involved with stopping a Cyberman attack on Voga, the planet of gold, to keep the resource of their major weakness to a minimum in the Cyber-Wars. The Doctor ultimately stopped them from blowing up the planet, defeating them once more. Finally reunited with the TARDIS, the Doctor received a call for help from the Brigadier via a space-time telegraph. (TV: Revenge of the Cybermen)

Returning to U.N.I.T.
The Doctor, Sarah and Harry met up with the Brigadier, and discovered that an alien race known as the Zygons were planning to use a Skarasen to attack London and abducting people to power body-prints that let them shape-shift into the forms of humans as disguises, the disappearance of the Duke of Forgill being among them. The Doctor and company had several close calls with the Zygons and eventually discovered the location of their spaceship, rescuing everyone, during which, the Doctor instigated the ship to self-destruct.

Discovering the plan was to have the Skarasen besiege Stanbridge House in a display of power, the group made haste to London. As the Brigadier and UNIT took care of the surviving Zygon commander, Broton, the Doctor found the trilanic activator used to control the Skarasen's movement and gave it to the Skarasen, who ate it and returned to Loch Ness. The Doctor prevented the destruction of the city, though the monster was still seen by the populace, and the Brigadier would have to quietly cover up the incident. After returning to Scotland to retrieve the TARDIS and bring the Duke back home, Harry chose to leave the TARDIS and find a more conventional means of transportation, while the Doctor managed to persuade Sarah to stay. (TV: Terror of the Zygons)

Journey to London
The Doctor and Sarah Jane next landed on Zeta Minor, thirty-thousand years in the future. Accused of killing the crew attempting to mine the planet for alternative sources to replace their dying sun, the Doctor instead found that the planet was the boundary between the normal universe and the anti-matter universe; taking any mineral from the planet would trap a ship there. The crew's leader, Professor Sorenson, had been infected with anti-matter and was fighting off its influence as he kept changing back and forth into a monster that mummified living beings. The Doctor tricked Sorenson into the TARDIS and kicked him into the pool of anti-matter, releasing the expedition ship and restoring the professor to normal. (TV: Planet of Evil)

Attempting to return to UNIT, the Doctor instead arrived at a priory in 1911, on the future site of UNIT headquarters. There, he had to prevent the last of the Osirans, Sutekh, from escaping his prison in Egypt and destroying the universe. Though unsuccessful in stopping Sutekh's servant, Marcus Scarman, from releasing him, the Doctor was able to delay Sutekh's trip through a time corridor to the priory by moving the corridor's threshold to the far future, thus effectively ageing him to death. Not realising his actions would cause the thermal balance to equalise, the Doctor accidentally set the priory on fire. (TV: Pyramids of Mars)

Afterwards, the Doctor seemingly found himself in a town Sarah Jane had previously visited for a newspaper article. They ultimately found that it was a facsimile of the town, not even actually on Earth, populated by androids under the control of the Kraals. The Kraals' own world had become uninhabitable, leading them to plan on wiping out Earth's population with a virus, then populating the planet themselves. Discovering Sarah had been replaced by an android, the Doctor found and rescued her. With the help of Harry Sullivan and UNIT, the Doctor was able to stop the aliens and rescue the townsfolk the Kraals replaced. (TV: The Android Invasion)

Missions for the Time Lords and Final Adventures with Sarah
The Doctor found his TARDIS forced to land on Karn by the Time Lords, as the Sisterhood of Karn had been crashing ships that passed Karn to protect what was left of their Elixir of Life. The Doctor used a firecracker to unplug the crevice the elixir came from, being promptly booted out. He then discovered the evil Time Lord Morbius was being resurrected in a patchwork body. Defeating him in battle of mindbending, the Doctor managed to reduce Morbius to a mindless beast that tumbled off a cliff to his death. However, the Doctor was left severely drained, but the Sisterhood allowed him to drink some their elixir, which restored the Doctor's health. (TV: The Brain of Morbius)

Being summoned by UNIT on behalf of the World Ecology Bureau, the Doctor saw pictures of a pod discovered in Antarctica. The Doctor and Sarah were flown to Antarctica, and found that the pod was Krynoid and had infected Charles Winlett. Outside, they also found another pod, and put it in the freezer. Before they could do anything for Winlett, he mutated further and became aggressive, going on a rampage. While trying to stop the new Krynoid, the Doctor failed to stop Scorby and Keeler, who worked for Harrison Chase, from finding the other pod, and escaping with it.

After the Krynoid was destroyed by Scorby's bomb, the Doctor and Sarah were rescued, and brought back to England. Investigating Chase Manor, the Doctor and Sarah encountered the Krynoid, who had infected Keeler, and had taken control of the body of Harrison Chase, planning to spread its seeds to take over Earth. While fighting Chase, the Krynoid and the plants animated by the creature, the Doctor called in UNIT, who worked with the RAF to destroy the Krynoid and the manor along with it. (TV: The Seeds of Doom)

During a trip in space, the Doctor accidentally brought the Helix Intelligence to San Martino, Italy, in the 15th century, where it planned to dominate the human race by using the Brotherhood of Demnos as its agents. Because the agents had been converted into pure energy beings by the Helix, the Doctor tricked the Brotherhood's leader, Hieronymous, into using all his energy until he vanished. Using his mask and cloak, the Doctor posed as him and used a device to drain the energy out of the rest of the Brotherhood, killing them and saving the Earth. (TV: The Masque of Mandragora)

The TARDIS landed in an English quarry, where it was buried by an explosion. The Doctor emerged unscathed, but Sarah was taken ill and so he accompanied her to hospital. There, he discovered she had come into contact with a stone hand and, when Sarah stole the hand and fled, followed her to Nunton Experimental Complex. Her wearing of a ring brought her under the control of Eldrad, a Kastrian scientist. The Doctor used a cooling duct to reach Sarah and brought her to her senses.

Eldrad restored herself using the reactor core. The Doctor agreed to take her back to Kastria, her homeworld, but only in the present, not her home time, as this broke the Laws of Time. On Kastria, Eldrad was injured by an acid-laden booby trap, so the Doctor and Sarah had to conduct her to a regenerator chamber. There she was restored to her male form. Eldrad discovered his people to be dead and asked the Doctor to return him to Earth so he could rule over humanity. Fleeing from him, the Doctor made use of his scarf, with Sarah holding the other end, to trip Eldrad, who fell into an abyss.

Back in his TARDIS, the Doctor received a telepathic summons from Gallifrey and was forced to leave Sarah behind, just as she herself had decided to return home. They both agreed they wouldn't forget one another as Sarah left, (TV: The Hand of Fear) but the Doctor had accidentally left her in Aberdeen, Scotland instead of South Croydon. (TV: School Reunion)

Return to Gallifrey
Discovering that the signal hadn't come from someone he knew, the Doctor returned to Gallifrey, just as it was the time of the election for Lord President, and theorised that the departing President was in danger. Stealing a robe to blend in, the Doctor attempted to prevent an assassination, but ended up framed for murdering the Lord President. To keep himself from being executed, the Doctor declared his own candidacy for Lord President. Believing the Matrix would give him clues as to who was behind this, the Doctor ended up in a mental duel with the culprit.

After finding the assassin, the Doctor learned that it was Goth, another Lord President candidate, who was being manipulated by the Master; since their last meeting, the Master, with no regenerations left, had degenerated into a rotting corpse. The Master was plotting to use the Eye of Harmony in an attempt to restart his cycle of regenerations by using the Sash of Rassilon to protect himself from the effects of the Black hole that would destroy Gallifrey as a side-effect.

After failing to convince the Master that, since the sash was damaged in the death of the old president, it would put the Master at risk, the Doctor fought him off. Though the Master managed to escape capture, the Doctor left his former teacher, Borusa, to lead Gallifrey as Cardinal, (TV: The Deadly Assassin) though, as the only candidate left, he was still eligible to gain the title of Lord President, even after leaving. (TV: The Invasion of Time)

Some time after, the Doctor met Albert Einstein for the first time, and tried to explain the realities of his Theory of relativity, but Einstein insisted that "he knew best." (TV: The Stones of Blood)

First Adventures with Leela
The Doctor returned to the planet colonised by the Mordee expedition centuries before, where he found that he was remembered as an evil god called "the Evil One" by the descendants of the colonists. Descendants of the colonist's survey team had become a warrior tribe called the Sevateem, while descendants of the technicians had become a technologically advanced tribe called the Tesh. Infiltrating the "Sacred Heart" of the old Mordee expedition ship with the help of one of the Sevateem, Leela, the Doctor cured the computer Xoanon of his multiple personalities. Leela, wanting to come with the Doctor, forced her way into the TARDIS, becoming his new companion. (TV: The Face of Evil)

On a Sandminer in the 23rd century, the Doctor and Leela were accused of killing members of the crew, and taken prisoner. They later discovered a madman named Taren Capel was murdering the crew, hoping to help his robot "brethren" rule humanity. However, the Doctor turned Capel's reprogramming of the robots against him by using helium gas to make his voice unrecognisable to them, leading to his death. (TV: The Robots of Death)

The Doctor received a summons from the Brigadier to investigate a strange object in Scotland, which he traced to one of the islands in Shetland. While the TARDIS' file on the island identified it as being uninhabited, the Doctor was attacked by Davy McTavit and Murdo Jamieson for being an "offlander", until Joanna Renwick stopped them. Learning that Leela had experienced something whilst rowing, the Doctor theorised that the lights in the sky were not a natural phenomenon, just as Viking artefacts started to attack Joanna. After falling down a hole while trying to find Angus Renwick, the Doctor was attacked by something in Viking armour, but he found his way onto Nardos' ship. After helping Leela to escape the flames, he and Leela travelled back in time accidentally and saw Angus' father during his mission in the Second World War. The Doctor worked out that the ship's defences were causing time to fracture. He was given the "wolf's eye" from a young Angus and used it to go back to the future, and tried to convince Nardos to stop his plans as it would destroy humanity. (AUDIO: The Helm of Awe)

The Doctor brought Leela to Victorian London and the pair encountered the magician Li H'sen Chang and his master, the self-styled Weng-Chiang, who was actually the 51st century criminal Magnus Greel. With the help of Henry Gordon Jago and Professor George Litefoot, the Doctor was able to stop Greel from using a failed time machine that would have destroyed reality, but when the attempt happened without a crucial part, Greel was caught in an explosion. (TV: The Talons of Weng-Chiang)

Continued Travels with Leela and Adopting K-9
At a lighthouse on Fang Rock, the Doctor and Leela discovered a Rutan Host who was planning to make use of the Earth's strategic placement in its race's war with the Sontarans. After all but he and Leela were killed by it, the Doctor destroyed the Rutan by blowing up the lighthouse. (TV: Horror of Fang Rock)

The Doctor, having become the host of the Nucleus, travelled to the Bi-Al Foundation medical centre in the year 5000, where its Swarm spread further, infecting numerous others. The Nucleus brought itself out of the Doctor's body and into the macro world to hatch more offspring. The Doctor travelled to Titan Base, where a hive of Swarm lay. The Doctor mixed the oxygen canisters with the methane atmosphere of Titan, blowing up the base and killing the Swarm. While there, he brought along Professor Marius' robot dog, K9, to fight the Swarm-infected humans. Unable to return to Earth with K9, Marius gave K9 to the Doctor as a gift. (TV: The Invisible Enemy)

The Doctor traced the source of a time hole to a group of scientists experimenting on a mysterious skull called Eustace. Much to his horror, the Doctor discovered "Eustace" was actually the skull of a Golden Core, responsible for creating humanity's darker side. Believing it could give them the power to rule the world, a cult used the scientist Thea Ransome as a medium for "Eustace". The cult's plan backfired, as the core simply began transforming them into Fendahl. The cult's leader, Maximillian Stael, committed suicide, preventing them from reaching the quota of thirteen Fendahl. The Doctor blew up their base, killing the transformed humans. (TV: Image of the Fendahl)

Arriving at Megropolis One on Pluto in the far future, the Doctor learned of the Company responsible for over-taxing the populace. He then discovered that Usurians had previously helped humanity move to Mars and then to Pluto for resources, but planned to leave them behind once Pluto was drained. He overthrew their representative, the Collector, trapping him in a jar in his true form of "seaweed", and set up a better economy. (TV: The Sun Makers)

Reaching the edge of the universe, the Doctor met a species the Time Lords helped evolve, whose destruction of their own planet because of their advancement in evolution led to the Time Lords' non-interference policy. He helped them locate and rescue fellow descendants of their species, taking them a new planet where they could start a better life. While helping them, the Doctor battled against the Oracle, a machine that enslaved the secondary descendants with the aid of robots. (TV: Underworld)

Lord President of Gallifrey
Returning once more to Gallifrey, and posing as vainglorious and power-mad, the Doctor sought and attained the office of Lord President from Borusa, who he had left in charge on his previous visit, as part of a scheme to save his home world from an invasion force of the Vardans who had contacted him for his aid. He was unable to confide his intent to double cross the Vardans in anyone but K9 due to the Vardans’ psychic abilities. He was inaugurated as President and crowned with the Crown of Rassilon, painfully connecting him to the Matrix.

As part of his plan, he had Leela exiled from the Citadel so that she would gather a resistance force. As he’d planned the Vardans arrived in force after K9 lowered Gallifrey’s transduction barrier, enabling him to track their point of origin and contain it in a time loop. However he was the confronted by an advance party of Sontarans who had used the Vardans’ invasion to gain access to Gallifrey. He retreated into the TARDIS and picked the Sontarans off through traps he set for them. Realising they would be unable to control Gallifrey, the Sontarans sought to destroy it so the Doctor was forced to retrieve the De-mat gun and use it to erase their leader, Stor, from history.

With his homeworld protected and Borusa once again in charge, the Doctor planned to resume his travels. But he learned Leela had fallen in love with a Gallifreyan guard named Andred and wished to remain with him; K9 likewise wished to stay with his "mistress". Though he seemed sad at first to lose both companions, the Doctor quickly pulled out a crate marked "K9 Mark II" from a storage area and grinned to himself. (TV: The Invasion of Time)

Quest for the Key to Time
After completing repairs on K9, the Doctor was called upon by the White Guardian to find the Key to Time's pieces and assemble it to bring the universe into balance. For his quest, the Doctor was given a new companion by the guardian, a Time Lady named Romanadvoratrelundar, whom the Doctor decided to call Romana. Despite not being too fond of each other, they managed to find the first segment to the Key on Ribos, which was disguised as a piece of Jethrik two con artists were using in their schemes. (TV: The Ribos Operation)

They set out to find the second segment on Calufrax, but instead landed on Zanak, where they became caught in the middle of a revolution between pirates, led by the Captain, and the psychically gifted Mentiads, who grew in number each time their planet materialised over another for riches and resources. Defeating the Captain and his nurse, the Doctor revealed to Romana that Calufrax, which was being held as a miniaturised trophy, was the second segment. (TV: The Pirate Planet)

The Doctor and Romana next journeyed to Boscombe Moor, where they found the third segment as a necklace belonging to the intergalactic criminal Cessair of Diplos, who had been posing as an ordinary Earth woman for centuries after she had stolen the segment while it was the Great Seal of Diplos, and used its transformative powers to take on different forms. Entering a ship stuck in hyperspace above a stone circle, the Doctor found her jailers and, as they did not know what she looked like, tricked them into identifying her, and they imprisoned her in the form of a stone. The Doctor then sent them through hyperspace to their intended destination. (TV: The Stones of Blood)

While looking for the fourth segment on Tara, the Doctor decided to take a relaxing fishing break while Romana went to look for it. Though successful in finding the piece to the Key, they both were forced into the political power struggle on Tara, as Romana was identical to a princess being held captive by Count Grendel, who wished to use her to claim the throne before his cousin. The Doctor exposed Grendel's plans and went on his way with Romana to continue the search. (TV: The Androids of Tara)

The search for the fifth segment brought the Doctor and Romana to Delta III where the Swampies worshipped an overgrown squid called Kroll, who was attacking a human mining base. Putting himself in harm's way, the Doctor found Kroll had swallowed the segment of the Key and was transformed by its properties. Allowing himself to be grabbed by the giant creature, the Doctor was able to use the tracer to reclaim the segment, transforming Kroll back into smaller squids in the process. Reclaiming the piece, the Doctor and Romana returned to search for the last segment. (TV: The Power of Kroll)

Searching for the final segment brought the Doctor and Romana to Atrios, a war-torn planet being attacked by the nearby computer-planet Zeros. There, they met the Shadow, an agent of the Black Guardian. Unfortunately, the final segment was in the form of Princess Astra of Atrios. The Doctor completed the Key, and then quickly separated it back into its original components to prevent the Black Guardian from getting it. Fearful the Black Guardian would return for revenge, the Doctor installed a randomiser in the TARDIS controls. (TV: The Armageddon Factor)

The New Romana
While repairing K9, the Doctor found Romana had regenerated into Astra's form, much to his displeasure. The randomiser landed the TARDIS on Skaro, where the Daleks were excavating the remains of the Kaled base to restore Davros. The Doctor also faced the Movellans, an android race at war with the Daleks. Having reached an impasse of logic, they both needed someone to reprogram their respective computers for "illogical" movements that would give either side an advantage. Winning the Movellans over, the Doctor allowed them to take Davros in cryogenic custody to await trial for his crime of creating the Daleks. (TV: Destiny of the Daleks)

The Doctor partially bypassed the randomiser to take Romana on a relaxing holiday to Paris, where the Doctor discovered a Jagaroth named Scaroth was splintered into twelve selves throughout time after his spaceship exploded; the explosion's radiation affected the primordial ooze, thus beginning life on Earth. The Doctor, Romana and detective Duggan succeeded in stopping Scaroth from preventing his spaceship from exploding. (TV: City of Death)

The Doctor later received a distress signal and arrived on Chloris, a lush and verdant world with only small quantities of metals, all of which were controlled by its ruler, Lady Adrasta. The Doctor was sent for execution, but managed to avoid it, deciding to investigate the creature he was supposed to be fed to. He found it to be an imprisoned Tythonian that had been sent by its people to set up a trade agreement with Chloris. Deciding to end Adastra's tyranny, the Doctor allowed the Tythonian to kill her and let a new reign of peace be set up between the two species of the planet. (TV: The Creature from the Pit)

The TARDIS then arrived on the space liner Empress, which had become locked together with a private ship, the Hecate, after colliding with it upon emerging from hyperspace. The Doctor and Romana met Tryst, who had a Continuous Event Transmuter machine. However, some Mandrels from Eden had somehow gotten on board. The Doctor later discovered he had been lied to, and Mandrels actually decomposed into the addictive drug vraxoin. The Doctor thwarted the drug-smuggling plan of Tryst and the pilot of the Hecate, separated the two ships, and returned the Mandrels to Eden. (TV: Nightmare of Eden)

Whilst in the middle of conducting TARDIS repair, the Doctor and Romana were caught in the middle of a sacrificial ceremony for a "god" called the Nimon. They discovered that this "god" was actually a parasite alien preparing Skonnos for the rest of its species. The Doctor succeeded in preventing the teleport from bringing more than two extra Nimon before the Nimon killed themselves as an accidental side-effect to their final gambit. With the help of the Anethans originally sent to be life-force sacrifices for the transporter, the Doctor destroyed the remaining Nimon before departing with Romana. (TV: The Horns of Nimon)

Shada
The TARDIS was sent a distress signal from Cambridge in 1979, sent by a retired Time Lord known as Professor Chronotis. (PROSE: Shada) Sources diverge on when and how their trip ended; the Doctor and Romana were kidnapped (TV: The Five Doctors) and then either returned without seeing Chronotis, (WC: Shada) or they were returned and saw the Professor as planned. (PROSE: Shada; HOMEVID: Shada)

While they were on a punt up the Cam, the Doctor and Romana were taken by a time scoop to the Death Zone on Gallifrey, but were caught in a time eddy and failed to arrive in the Death Zone. (TV: The Five Doctors) They were returned to the Cam (HOMEVID: The Five Doctors) to the time they left (HOMEVID: Shada) when Borusa was sealed in the Tomb of Rassilon. (TV: The Five Doctors)

The Doctor met Chris Parsons and Clare Keightley, who helped him to fight Skagra. Skagra attempted to steal The Worshipful and Ancient Law of Gallifrey so he could break into Shada and retrieve Salyavin from his imprisonment. Without realising that Salyavin had escaped, and was living in retirement under the alias "Chronotis", the Doctor had to foil Skagra's plot, which involved taking Salyavin's power to project his mind into other minds, so he could use it to shift his mind into the minds of all life in the universe, using his Krargs. After defeating Skagra, the Doctor imprisoned him in his own ship, and decided to allow Salyavin to remain on Earth. (PROSE: Shada; HOMEVID: Shada)

Final Travels with Romana
Following an issue with the TARDIS randomiser, the Doctor and Romana touched down at Sentry Castle to fix the issue. However, upon arrival, he was quickly arrested and taken to the dungeon, whilst Romana was taken away to be interrogated by the castle's owner, Lord Vexell. Together with Vexell's daughter Francisca and fellow inmate Niersicht, the Doctor was able to escape from his prison to find Romana. They came to realise that Vexell had usurped his position from Niersicht, and managed to turn the castle guards against Vexell, forcing him into Niersicht's former position. After the Captain of the guards helped the Doctor fix his randomiser, they set off again, knowing that this had caused them to stall enough for the Black Guardian to be able to easily find them. (TV: The Castle of Doom)

Arriving on Tigella, a planet he visited centuries earlier, the Doctor was accused of stealing the Dodecahedron, but was saved from punishment when it was discovered someone was posing as him. He discovered Meglos, last of the Zolfa-Thurans, had stolen the object to power a device that could destroy planets. The Doctor stopped Meglos by redirecting his machine's laser back at it, destroying him. While preparing to leave for a new adventure, the Doctor received a message from Gallifrey, demanding the return of Romana. (TV: Meglos)

The Doctor and Romana next arrived on a technologically advanced planet, where they learned of a human ship called the Hydrax that came there several years ago. They met the Three Who Rule, discovering their castle was actually the Hydrax and they were vampires, converted by the Great Vampires' king, an old nemesis of the Time Lords. During the Time of Arising, in which the King would be resurrected and return to this universe, the Doctor launched an escape craft from the Hydrax through its heart, killing the ancient creature. (TV: State of Decay)

When the Doctor and Romana arrived on the planet Erinella, the Doctor was accused by Hadale, a warrior of having poisoned Princess Orina to aid the criminal Anepco's stealing of her. He managed to clear his name, and went briefly with Hadale to rescue Orina, but turned back, leaving his companions behind, so as to get something from the TARDIS. However, the randomiser malfunctioned and sent the Doctor back in time so that he met Orina before she was kidnapped. Trying to allay her fears, the Doctor told her to act poisoned after drinking some lemonade, not realising that the drink was genuinely poisonous to her species. Upon realising his mistake, the Doctor piloted the TARDIS back to the present and helped rescue Orina, admitting his mistake to Hadale, who forgave him. (TV: Dragons of Fear)

The Doctor landed on Halley's Comet. There, he had to engage in a battle of minds against the High Priest Levish to explain about the outside universe. When the comet was under attack by Captain Torek and his men, the Doctor oversaw Halley's Comet's defences. He eventually convinced lieutenant Tela to go against orders and blow Torek up, whilst he escaped in a pod. (TV: Into the Comet)

Once the TARDIS made it back to Gallifrey, the randomiser was sabotaged by Supreme Treasurer Halvak, causing several timelines of the Doctor and Romana to converge. The Doctor was caught up in amongst all the other Doctors, many of whom looked much like him. He would eventually prove himself to be the true Doctor to Romana, and together with Spandrell and Andred, they confronted Halvak and had him deposed from power. Romana stepped up to take up his position, and the Doctor bade her good luck as he left. (TV: Sealed Orders)

Personality
The Fourth Doctor was bohemian-like in nature and stood apart from others, even his own people. He delighted in keeping both friends and foes alike off guard with oddball humour and curious pranks, often playing the fool to lull his opponents into underestimating him, believing that there was "no point being [a] grown-up if you can't be childish sometimes". (TV: Robot, Revenge of the Cybermen, The Deadly Assassin, The Invasion of Time, The Armageddon Factor, City of Death) Although he was generally peace-loving and kind-hearted, the Doctor would react with explosive fury when provoked. (TV: Genesis of the Daleks, Planet of Evil, Pyramids of Mars, The Brain of Morbius, The Seeds of Doom, The Invasion of Time, The Pirate Planet, The Castle of Doom, Into the Comet)

The Doctor could be pedantic at times, often acting erratically in crisis, reacting to others with witty wisecracks and constantly changing his direction of speech. (TV: Robot, Genesis of the Daleks, Revenge of the Cybermen, Terror of the Zygons, Pyramids of Mars, The Brain of Morbius, The Seeds of Doom, The Face of Evil, The Talons of Weng-Chiang, The Invasion of Time, The Stones of Blood, The Armageddon Factor, Destiny of the Daleks, City of Death, The Castle of Doom, Sealed Orders)

The Fourth Doctor had a consistently anti-authoritarian attitude, with little tolerance for religious dogma (TV: The Face of Evil, The Brain of Morbius, Underworld, The Stones of Blood, The Power of Kroll, Into the Comet) or nationalism, (TV: Robot, The Armageddon Factor) but held a great respect for the White Guardian. (TV: The Ribos Operation) He generally maintained his distance from the Time Lords, and resented that they were capable of re-entering his life when they deemed it necessary. (TV: Genesis of the Daleks, The Brain of Morbius) Not only was he more inclined towards a solitary existence, (TV: The Deadly Assassin) he also emphasised his distance from humanity, (TV: Pyramids of Mars) though also stated on multiple occasions that he found mankind to be his favourite species. (TV: The Ark in Space, The Masque of Mandragora)

He was almost completely devoid of fear, reacting unfazed to threats of pain and death, (TV: The Android Invasion, The Brain of Morbius, The Seeds of Doom, The Stones of Blood, The Armageddon Factor, City of Death, The Castle of Doom) and assassination attempts. (TV: The Face of Evil, The Robots of Death, The Talons of Weng-Chiang) When it seemed he was doomed, he resolved to accepting his fate, often lamenting the long life he had, (TV: The Power of Kroll) and the friends he had with him. (TV: The Horns of Nimon, Sealed Orders)

He liked to drink ginger beer. (TV: The Android Invasion)

Despite his charm and offbeat humour, the Fourth Doctor could be intensely brooding, serious and even callous at times, (TV: Pyramids of Mars, The Seeds of Doom, The Invasion of Time, Into the Comet) and would keenly scrutinise his surroundings even when playing the fool. When Sarah upbraided him over his callousness at the sight of Laurence Scarman being killed by the animated corpse of his own brother, the Doctor reminded her of the larger issue of stopping Sutekh. (TV: Pyramids of Mars) He would be furious with those he saw as stupid, frivolous, misguided, or evil. (TV: The Face of Evil, The Robots of Death, Nightmare of Eden, The Castle of Doom, Dragons of Fear, Into the Comet) When taking charge, he was authoritative to the point of egocentricity, though he eventually proved himself as the only one capable of solving the situations he found himself in. (TV: Revenge of the Cybermen, The Armageddon Factor)

He was also not against taking a life in extreme circumstances, (TV: The Brain of Morbius, The Invasion of Time) but would scold Leela for unnecessary killing. (TV: The Face of Evil) Though he was much less inclined to use physical violence than his predecessor, the Fourth Doctor would react aggressively if he had no alternative but to defend himself. (TV: Planet of Evil, The Seeds of Doom, The Castle of Doom)

He improvised non-lethal weaponry when necessary, (TV: Planet of Evil) but was also willing to use more lethal weaponry, like the De-mat Gun and Earth firearms, if necessary. (TV: The Seeds of Doom, The Talons of Weng-Chiang, Image of the Fendahl, The Invasion of Time)

He threatened to deactivate Davros' life-support machine to coerce him into destroying the Daleks, (TV: Genesis of the Daleks) fatally electrocuted an attacking Tesh under Xoanon's control, (TV: The Face of Evil) and seemed to have nothing against Leela killing random attackers, as long as she kept quiet about it. (TV: The Talons of Weng-Chiang) He was also willing to sacrifice himself in order to kill Davros via an explosive device in an attempt to prevent the Daleks harnessing their creator. (TV: Destiny of the Daleks)

Nevertheless, the Doctor still had a strong moral code, such as confronting J.P. Kettlewell about how the ends never justified the means, (TV: Robot) and when he faced the dilemma of whether to destroy the Daleks, stating that if he did, he would be no better himself than the Daleks. (TV: Genesis of the Daleks) He was also appalled at the actions of the Captain, (TV: The Pirate Planet) and refused to listen to Professor Tryst's attempts to justify drug-running in order to fund his scientific work, simply telling him to go away. (TV: Nightmare of Eden) He also attempted to save Harrison Chase from death, despite Chase previously attempting to kill him, (TV: The Seeds of Doom) and convinced both the Captain of the Guard (TV: The Castle of Doom) and Lieutenant Tela (TV: Into the Comet) to join his side after presenting them with the error of their, or other peoples', ways.

The Doctor was not above the occasional act of hypocrisy, telling Harry Sullivan that it was a waste to throw something away, immediately before disregarding a piece of metal that had saved his life. He also told Harry it was "a mistake to clutter one's pockets", despite he himself keeping a large variety of things in his own pockets. (TV: The Sontaran Experiment) He later berated Romana for assuming the worst, and then stated himself that things usually were at their worst, (TV: The Armageddon Factor) and took a liking to her second incarnation when she mimicked his dress sense, despite previously telling her that "external appearances weren't important". (TV: Destiny of the Daleks)

He was also unwilling to admit to any wrongdoing on his part. (TV: The Sun Makers)

He was also not averse to winding up his companions on occasion, such as questioning Sarah Jane's integrity to encourage her to manoeuvre herself out of a ventilation shaft. (TV: The Ark in Space) He later fooled Leela into playing with a yo-yo for an extended period of time, with her believing it was a form of magic. (TV: The Robots of Death) On another occasion, he caused Romana to panic when he pretended to be corrupted by the Key to Time. (TV: The Armageddon Factor)

The Fourth Doctor would affectionately call his companions his "dears". (TV: Sealed Orders)

Unlike his other incarnations, the Fourth Doctor would rarely invite others to travel with him, a majority of his companions inviting themselves aboard the TARDIS, (TV: Robot, The Face of Evil) or having someone else persuade the Doctor to let them join him. (TV: The Invisible Enemy, The Ribos Operation) Nevertheless, the Doctor had a close friendship with his companions, and worried about their safety. (TV: The Hand of Fear) He considered Sarah Jane Smith, Leela and K9 Marks I and II to be his best friends. (TV: The Seeds of Doom, The Invasion of Time, The Pirate Planet) However, he viewed Harry Sullivan as an imbecile, (TV: Revenge of the Cybermen) and believed that any intelligence that Harry showed was due to his influence. (TV: The Ark in Space)

He was, for the most part, oblivious to other people's attractiveness, believing that telling Countess Scarlioni that she was "probably beautiful" was a compliment. (TV: City of Death)

Unlike his predecessors, the Fourth Doctor did not maintain a close working relationship with UNIT, reacting with anger and disdain when he was recalled back to Earth by the Brigadier. (TV: Terror of the Zygons, Pyramids of Mars) Except for a handful of occasions, the Doctor kept his distance from the organisation. (TV: Robot, Terror of the Zygons, The Android Invasion, The Seeds of Doom)

In her first incarnation, Romana stated that the Doctor was "capricious, arrogant, self-opinionated, irrational, and [didn't] even know where [he was] going". (TV: The Armageddon Factor)

Habits and Quirks
The Fourth Doctor would often have jelly babies with him and offered them as a greeting. (TV: Robot, The Ark in Space, The Face of Evil, The Robots of Death, The Talons of Weng-Chiang, Image of the Fendahl, The Sun Makers, The Invasion of Time, Destiny of the Daleks, The Horns of Nimon, Into the Comet, Sealed Orders) His favoured choice was the orange coloured jelly babies. (TV: The Invasion of Time)

He would often instruct his companions to follow him by saying, "Come on", even saying it when he was following them. (TV: The Ark in Space, The Hand of Fear, The Talons of Weng-Chiang, The Ribos Operation, Destiny of the Daleks, City of Death) He would often ask others if they were listening to him, (TV: The Armageddon Factor) and often told K9 to "shut up". (TV: The Stones of Blood, The Armageddon Factor, Destiny of the Daleks) In the later parts of his life, the Doctor would stretch the last syllable of "Hello" when greeting himself. (TV: The Castle of Doom)

He often talked to himself, with Sarah Jane Smith stating he did so "mostly because [he was] the only person who [knew] what [he was] talking about", (TV: The Ark in Space, The Invasion of Time) and would often describe an inhumane adversary as an "unspeakable abomination". (TV: The Sontaran Experiment, The Brain of Morbius)

The Fourth Doctor was prone to flashing his upper teeth when grinning. (TV: Robot, The Sontaran Experiment, Revenge of the Cybermen, Terror of the Zygons, The Masque of Mandragora, The Robots of Death, The Sun Makers, The Invasion of Time, The Ribos Operation, City of Death, Dragons of Fear)

When relaxing, the Doctor tended to put his foot up on a ledge and lean back, often placing his hat over his face as he slept. (TV: The Androids of Tara) To allure a sense of mystery, the Doctor would often tap his nose when keeping secrets. (TV: Robot, The Brain of Morbius, The Creature from the Pit)

He would play with a yo-yo to relax. (TV: The Ark in Space, The Android Invasion, The Brain of Morbius, The Seeds of Doom) He also started a trend of talking to the TARDIS, (TV: The Deadly Assassin, The Horns of Nimon) constantly showing affection for his magnificent machine by kissing it and caring for it when it got damaged. (TV: The Invasion of Time, The Ribos Operation)

Skills
Much like his immediate predecessor, the Fourth Doctor was very physical, being an excellent runner and fighter, (TV: The Sontaran Experiment, Genesis of the Daleks, Planet of Evil, The Android Invasion, The Deadly Assassin, The Face of Evil, The Talons of Weng-Chiang, City of Death, The Castle of Doom) He was also shown to be a highly skilled swordsman, being able to hold his own against multiple opponents, (TV: The Masque of Mandragora) and the finest swordsman on Tara. (TV: The Androids of Tara)

Showing incredible accuracy, the Doctor was able to hit a bullseye on a dart board, (TV: The Android Invasion) strike a strand of rope with a crossbow, (TV: The Face of Evil) and throw an axe at Magnus Greel's distillation machine to free Leela. (TV: The Talons of Weng-Chiang)

The Doctor possessed telepathic powers, allowing him to communicate with other telepathic users. While other incarnations had to make physical contact to use telepathy, the Fourth Doctor could project his mind over long distances. This also allowed him to guide the Mentiads into using their telekinetic powers to move a spanner in order to ruin the plans of the Captain and Xanxia. (TV: The Pirate Planet) Due to, what he described as, his complex mind, (TV: The Invasion of Time) the Doctor was able to immunise himself from telepaths, such as Li H'sen Chang, (TV: The Talons of Weng-Chiang) and the Vardans. (TV: The Invasion of Time)

The Doctor also claimed to be a master hypnotist, hypnotising Sarah Jane simply by laying his hands on her temples. (TV: Terror of the Zygons, The Hand of Fear) Other times, the Doctor would instead use a fob watch to hypnotise someone, (TV: The Ribos Operation) or break another hypnotists hold on them. (TV: The Talons of Weng-Chiang) He was also able to use vocal commands to free Leela from Xoanon's mental control, (TV: The Face of Evil) and to hypnotise Rodan into assisting K9 in constructing the De-mat Gun, and then break her hypnosis with the snap of his fingers. (TV: The Invasion of Time)

He could commandeer and ride a horse with ease. (TV: The Masque of Mandragora)

The Doctor could speak Mandarin and Cantonese, among other dialects. (TV: The Talons of Weng-Chiang)

Like several of his incarnations, his pockets appeared to be dimensionally transcendental, as he carried a large array of items in his pockets, which included a seemingly endless supply of Jelly babies, a galactic passport, (TV: Robot) a cricket ball, (TV: The Ark in Space) a magnifying glass, gemstones, handcuffs, an etheric beam locator, (TV: Genesis of the Daleks) a lockpick, (TV: Pyramids of Mars) a football rattle, (TV: The Masque of Mandragora) a magician's cane, (TV: The Hand of Fear) a clockwork egg-timer, (TV: The Face of Evil) a breathing tube, (TV: The Robots of Death) a yo-yo, a toy Batmobile, a stuffed mouse, (TV: The Talons of Weng-Chiang) a barrister's wig, (TV: The Stones of Blood) an instant camera, (TV: City of Death), a small bottle of lemonade, (TV: Dragons of Fear) a glass marble, a guide book for the Black Pyramid, a jeweller's eyeglass, the TARDIS key, a draw-string purse containing coins from many different planets including a 1000 credit piece, Edwin Carver's electronic notebook, and the scarab. On one occasion, he even dropped a cup containing a hot beverage into his pocket. (TV: The Power of Kroll)

The Doctor could also perform magic tricks, (TV: The Talons of Weng-Chiang) and judge character keenly, almost instantly knowing whom to trust. (TV: The Ribos Operation)

Physical Appearance
The Fourth Doctor was notable for having large, expressive blue eyes, a large hooked nose, a round chin, bright white teeth and a large head of wild curly brown hair, (TV: Planet of the Spiders, Robot)

Upon first seeing his reflection, the Doctor thought his "nose [was] a definite improvement" over his predecessor's, but was unsure about his ears in comparison. (TV: Robot)

Clothing
In stark contrast to the elegant and refined figure of his previous incarnation, the Fourth Doctor was an unkempt, bohemian-looking figure, with his most distinctive item of clothing being a series of long, rainbow-styled scarfs that varied in length and pattern formation, (TV: Robot, Image of the Fendahl, The Ribos Operation, Shada) which had originally been knitted for him by Madame Nostradamus. (TV: The Ark in Space)

His dark curly hair was often partially hidden by a floppy brown fedora. (TV: Robot)

Aside from his scarf, the Doctor's first outfit consisted of a rust-orange corduroy blazer with elbow patches, baggy grey tweed trousers, a dark brown cardigan with diamond shapes adorning the front, a white dress shirt, an emerald green skinny tie, and ankle-high leather shoes. (TV: Robot)

Eventually, his style stabilised into a frock coat, trousers, and some form of a cravat or tie with a checked-styled waistcoat, a fedora, and his scarf. (TV: Terror of the Zygons) He later abandoned neck wear in favour of an open-necked shirt, with a likewise unbuttoned waistcoat. (TV: Underworld) He also varied his footwear to include knee-high leather boots. (TV: The Deadly Assassin)

He wore several frock coats of different colours, including a burgundy coat, (TV: Pyramids of Mars) a light grey beige tweed coat, (TV: The Android Invasion) and a dark brown coat. (TV: The Face of Evil) He sometimes adorned his coats with lapel pins and brooches in various shapes, such as a flock of geese, (TV: The Power of Kroll) or an artist's pallet with tubes of paint. (TV: City of Death) He occasionally wore trench coats as well, including a light brown one with dark brown trim, (TV: The Power of Kroll) and a plum velvet one. (TV: The Castle of Doom)

Professor Frederick Marius remarked that the Doctor looked like a "space vagrant". (TV: The Invisible Enemy)

Casting
Actors considered for the role of the fourth incarnation included Michael Bentine (who was turned down for wanting too much influence over the scripts), Bernard Cribbins (who wanted to institute more violence in the show), Graham Crowden, Richard Hearne (who was turned down for wanting to play the Doctor like his Mr. Pastry character), Fulton Mackay and Jim Dale. Tom Baker was cast based on his role as the villain Koura in The Golden Voyage of Sinbad.

Season 11

 * Planet of the Spiders

Season 12

 * Robot
 * The Ark in Space
 * The Sontaran Experiment
 * Genesis of the Daleks
 * Revenge of the Cybermen

Season 13

 * Terror of the Zygons
 * Planet of Evil
 * Pyramids of Mars
 * The Android Invasion
 * The Brain of Morbius
 * The Seeds of Doom

Season 14

 * The Masque of Mandragora


 * The Hand of Fear
 * The Deadly Assassin
 * The Face of Evil
 * The Robots of Death
 * The Talons of Weng-Chiang

Season 15

 * Horror of Fang Rock
 * The Invisible Enemy
 * Image of the Fendahl
 * The Sun Makers
 * Underworld
 * The Invasion of Time

Season 16

 * The Ribos Operation
 * The Pirate Planet
 * The Stones of Blood
 * The Androids of Tara
 * The Power of Kroll
 * The Armageddon Factor

Season 17

 * Destiny of the Daleks
 * City of Death
 * The Creature from the Pit
 * Nightmare of Eden
 * The Horns of Nimon
 * Shada

Season 18

 * The Castle of Doom
 * Meglos
 * State of Decay
 * Dragons of Fear
 * Into the Comet
 * Sealed Orders

Season 19

 * Space-Whale
 * Vayleon
 * Kinda
 * The Visitation
 * The Killer's Portrait
 * The Psychrons