26th century

By the 26th century, the first Earth Empire had formed from an Earth-centred alliance of planets. It lasted until the late 30th century. Earth's single, planet-wide government was called EarthGov. (PROSE: Missing Adventures: Home) This century was characterised by tensions which existed between the Earth Empire and other powers including the Empire of the Draconians, the Daleks, the Korven, and the Cybermen. (TV: Frontier in Space, The Korven, Earthshock) The tensions against the Daleks culminated in the brutal Second Dalek War. (PROSE: Prisoner of the Daleks)

Events
At the start of the century, the Earth Empire was embroiled in the Orion War against the Orion androids. In 2503, after eight years of fighting, the war had reached a stalemate; to break it, the Earth Military sent an agent to the Garazone System to retrieve Cyber-Technology from a derelict Cyberman Star Destroyer leftover from the Cyber-Wars. The agent was in reality an android double agent, Deeva Jansen, who wished to discover the secrets of Cyber-conversion to use on their human prisoners of war. The Eighth Doctor dissuaded her and saw to the destruction of the ship, and all the Cybermen aboard, in an ion storm. (AUDIO: Sword of Orion) Both sides continued to investigate Cyber-technology; the Seventh Doctor encountered android agents investigating a Cyber tomb on Tasak, (AUDIO: Kingdom of Silver) and the Earth Military set up the Scorpius project to research Cyber-technology. (AUDIO: Scorpius)

Twenty years into the Orion War, Scorpius had fallen under the control of a Cyber-Planner. Scorpius arranged the rise of Karen Brett to Earth President and used her to seize control of the Earth Government, beginning Cyber-conversions under the guise of “special commando units”. Brett herself was eventually converted into a Cyber-Leader, (AUDIO: Scorpius, Fear, Conversion) and dispatched to awaken the Master Hibernation Unit adrift in the remains of Telos. Android forces, aided by Brett’s former friend Liam Barnaby, foiled the expedition. (AUDIO: Telos) With Brett lost, Cybrid Paul Hunt became the public face for the Cyber-Planner’s regime on Earth and conversions accelerated, leading to a resistance forming. (AUDIO: Outsiders, Terror, Machines) The resistance helped android agent Samantha Thorn reach the Planner and she interfaced with it, persuading it that logically the Cybermen should withdraw from Earth as the situation would degenerate into a war they could not win. After leaving Earth, the Planner’s forces were eventually ambushed in space by android ships. (AUDIO: Extinction)

Early in the century, the Sontarans and the Rutans took their war to Chelsea 426. The Tenth Doctor stopped the Rutans and the Sontarans left before the colony collided with a Great White Spot. The Doctor prevented this as well. (PROSE: The Taking of Chelsea 426)

In 2520, a misunderstanding between human and Draconian spaceships caused a brief, but highly destructive, war between the empires. A fragile peace was agreed which held for two decades. (TV: Frontier in Space)

A new race of Cybermen, dubbed "CyberNeomorphs" by the ArcHivist Hegelia, proliferated during this century. (PROSE: Killing Ground) In 2526, a conference was held on Earth to formalise an alliance against the Cybermen. The Cybermen made two attempts to destroy Earth during the event; first with a Cyber-bomb and then by hijacking an Earth-bound freighter to collide it with the planet. Both efforts were foiled by the Fifth Doctor and his companions. (TV: Earthshock)

By mid-century, much of what had been the southern United States had sunk under the "Mississippi Sea" — probably a much-expanded Caribbean Sea. (PROSE: Home)

In 2540, the Daleks worked with on Operation Divide and Conquer, (AUDIO: The Dalek Conquests) planning to incite a second war between Earth and Draconia to pave the way for a Dalek conquest. The Third Doctor and Jo Grant discovered the plot and managed to alert the humans and Draconians. (TV: Frontier in Space) With the aid of the Time Lords, the Doctor pursued the Gold Dalek to Spiridon. There he and Jo aided a Thal campaign against the Daleks, entombing the 10,000 strong Dalek army being assembled there in ice. (TV: Planet of the Daleks)

The Earth and Draconian Empires united to face the threat of the Daleks, beginning the Second Dalek War, (PROSE: Love and War) though the two empires proved unwilling to cooperate meaningfully in the long term and the war protracted. (COMIC: Star Tigers, AUDIO: Out of Time) Earth’s worst criminals were given a choice between execution or joining the war effort as a Dalek Killer; among them was Abslom Daak. (COMIC: Abslom Daak... Dalek Killer) The planet Heaven was used as a burial site for both humans and Draconians. In 2570 it was targeted by the Hoothi who were defeated by the Seventh Doctor. (PROSE: Love and War, AUDIO: Love and War) The war lasted for over forty years and many planets were destroyed in the conflict. The war ended after the Tenth Doctor and the crew of the Wayfarer destroyed the Dalek ship Exterminator and its Dalek crew, leaving its leader, Dalek X, for dead. With the Dalek Fleet having lost the initiative, (PROSE: Prisoner of the Daleks) the war ultimately "fizzled out". (PROSE: Deceit)

Notable features
Space travel appeared to be significantly faster by the end of the century; the approximately twenty-seven thousand light-year trip from Earth, near the edge of the galaxy, to Dellah, near its core, took about eleven months. (PROSE: Oh No It Isn't!) Space travel could still be lengthy however and it was common to sedate passengers for the longer trips. (PROSE: Biology Lesson on Mal Oreille)

Thanks to genetic engineering, humans no longer had wisdom teeth. (PROSE: Dry Pilgrimage)

Earth's Moon was used as a penal colony. (PROSE: Home)

Notable individuals
Bernice Summerfield grew up in this century. (PROSE: Just War)

Abslom Daak and the Star Tigers fought Daleks at this time. (COMIC: Abslom Daak... Dalek Killer, Star Tigers)

Ace lived here for three years when she decided to leave the Seventh Doctor and join Spacefleet. (PROSE: Deceit)

Laura Tobin lived in this century as a human before her transformation into the Eighth Doctor's companion Compassion. (PROSE: Interference - Book One, Interference - Book Two)

Space Major Jon Bowman lived in this century. He was in charge of a starship with a crew of bounty hunters during the Second Dalek War, which he helped the Tenth Doctor to end. He and another member of his crew, Koral, survived. The other three died. (PROSE: Prisoner of the Daleks)

Alternate timeline
In a potential history shown by the Eleventh Doctor to Jean-Luc Picard, the Cybermen, having integrated both the Doctor's N-Space and Picard's parallel universe before conquering the Borg, concluded their campaign to convert the galaxy by crushing the last holdout of free humanity on Earth. (COMIC: Assimilation²)

Behind the scenes
Doctor Who: Cybermen states that the Neomorph subspecies of Cybermen was forged by surviving CyberNomads and the CyberTelosians on Telos around the year 2500.

The Dalek Handbook claims that grey Daleks succeeded the silver Daleks as drones following the Dalek Civil War, dated to the 41st century, and that their presence in the 26th century Operation Divide and Conquer and the Spiridon campaign was indicative of continued operations to overwrite history in the Daleks' favor, with the silver Daleks seen in the Exxilon Gambit being 27th century-native Daleks that had been subsumed into future Dalek forces.