4221
From Tardis Wiki, the free Doctor Who reference
43K2.1 was a date in the 42nd century, sometime prior to the year 4126. Sanctuary Base 6 was assaulted by the Beast, which was defeated by the Tenth Doctor and Rose Tyler. (TV: The Impossible Planet / The Satan Pit)
The setting in the 42nd century was confirmed by the Tenth Doctor when he spoke of this encounter again to Donna. (TV: Planet of the Ood)
