51st century

Ongoing

 * Humanity was sexually liberal, having both same-sex relations and inter-species ones. (DW: The Doctor Dances) Same-sex marriage was considered normal, even for church clerics. (DW: A Good Man Goes to War)
 * Another Ice Age affects Earth during this time. (DW: The Talons of Weng-Chiang, EDA: Emotional Chemistry)
 * Earth begins to be abandoned by the rich and powerful as the sun goes supernova. Those left behind have fractured into millions of nation-states ("Alliances") battling through the ether in the Transmat Wars. (DWM: The Keep)
 * The Supreme Alliance, at the initiative of its minister of justice Magnus Greel, experiments with time travel using a method based on double nexus particles and zygma beam, but this proves to be a dead end. Magnus Greel was said to be the first Human to travel through time, but became horribly disfigured for it. (DW: The Talons of Weng-Chiang)
 * The Time Agency operated out of this century, but it was closed again in same century, and only seven agents remained. (DW: The Talons of Weng-Chiang, The Empty Child, TW: Kiss Kiss, Bang Bang)
 * The Church was a faith-based military organisation primarily responsible for interstellar security, protecting human populations, and special covert operations. Regular military ranks have been replaced by offices such as Bishop, Cleric and Verger. (DW: The Time of Angels, Flesh and Stone)
 * Human bodies in this period have been evolved to produce more highly evolved pheromones, which make them more sexually attractive than baseline Humans. (TW: Fragments)
 * "Homunculi" such as clones, cross-breeds, fighting-machines and other artificial intelligences outnumber Humans by 13 to 1. (BBV: In the Year of the Cat)

Major Events

 * 5080 - The year of the Great Breakout. Humanity spreads through the Galaxy. Destruction of the moon, Titan. (DW: The Invisible Enemy)
 * Early 51st century - The Icelandic Alliance fell and the Supreme Alliance, of whom Magnus Greel was Minister of Justice, rose in its stead. The Supreme Alliance committed a number of war crimes and was brought down by the Filipino Army at the Battle of Reykjavik, which the Doctor witnessed. (DW: The Talons of Weng-Chiang)
 * Early 51st century - Magnus Greel kills approximately 100,000--a deed that earns him the epithet "Butcher of Brisbane".
 * Late 51st century - The Time Agency formed and began employing Time Agents for missions in other time periods. (DW: The Empty Child) It would later close down, having only seven agents left (TW: Kiss Kiss, Bang Bang), presumably sometime later than 5145. (DW: The Pandorica Opens)

Minor Events

 * 5000: A ship en route to Titan Base encounters a virus of unknown origin, it is revealed through the intervention of the Doctor to be a sentient virus known as The Swarm. Through his intervention the Doctor is infected and transported by Leela of the Sevateem to the Centre for Alien Biomorphology, where both she and the Doctor are assisted by Professor Marius to defeat/cure the virus. (DW: The Invisible Enemy)
 * 5094 - Jack Harkness is voted "rear of the year" (TW: Kiss Kiss, Bang Bang)
 * Unknown : The weapons factories of Villengard are destroyed by the Doctor and replaced by a banana grove. (DW:The Doctor Dances)
 * Unknown - The spaceship SS Madame De Pompadour becomes disabled. Adrift in the Dagmar Cluster, its computer core begins cannibalizing the crew for parts; when this proves ineffective, it creates Clockwork Droids and attempts to kidnap the original Madame de Pompadour from the 18th century. (DW: The Girl in the Fireplace)
 * Unknown- The Doctor and Amy Pond, along with River Song witness the crash of the Byzantium (ship), then confront the last of the Weeping Angels in the Maze of the Dead. (DW: The Time of Angels/Flesh and Stone)
 * Unknown - The Doctor and Donna Noble visit The Library where they face an infestation by the Vashta Nerada, and the Doctor meets River Song for the first time in his personal timeline (but not in hers). The nature of The Library is revealed as the Doctor retrieves the consciousnesses of some 4,022 humans who were uploaded to the memory banks of the supercomputer, CAL. (DW: Silence in the Library / Forest of the Dead)

Notable Individuals

 * Jack Harkness, John Hart, Gray and Magnus Greel all came from this century.
 * River Song was working in this century, and ultimately ended up preserved in the CAL computer during this time, and as of A Good Man Goes to War, it's been confirmed that she was born in this century on the asteroid Demon's Run. However, it is currently unknown where she spent the rest of her childhood. K9 is a resident of this century but was created in the previous.