4000

In the year 4000, the Daleks held a meeting with representatives from seven outer galaxies to plot the invasion and overthrow of human-occupied space. (TV: Mission to the Unknown)
Six months later, the First Doctor became involved with the Space Security Service's investigation into the Daleks, Mavic Chen and the Time Destructor. This culminated in the destruction of Kembel. (TV: The Daleks' Master Plan) The Great War began in the wake of this event. (PROSE: The Evil of the Daleks)
After the death of Mavic Chen, a dynasty of his descendants slowly transformed the relatively democratic Galactic Federation into a new incarnation of the old Earth Empire, which had fallen approximately nine centuries earlier. (PROSE: The Crystal Bucephalus)
The Fourth Doctor, Leela and Charlotte Willis also visited this year. However, the Doctor believed that history had been altered. In this timeline, Earth was invaded by the Pantophagen due to Jalnik's time travel experiments. However, the Doctor prevented them from ever coming to Earth in the first place. (AUDIO: The Foe from the Future)
The Tenth Doctor dated the saying "Never turn your back on a dead Dalek" to "about 4000". (PROSE: I Am a Dalek)