Planejammer Campaign Setting
The broad sweep of history is divided, roughly, into 9 eras. These era’s are largely based upon the rise and fall of Humaniti and their empire of the stars. While other races, particularly the other Major Races, may have a differing division of eras, the Imperial Encyclopedia uses the Humaniti centric one.
Years of the long silence (-300,000 to -9234)
Years of rise of the Vilani (-9235 to -4044)
Years of the First Imperium (-4045 to -2421)
Years of the Interstellar wars (-2422 to -2203)
Years of the Second Imperium (-2204 to -1776)
Years of the Long Night (-1775 to 0)
Years of the Third Imperium (0 to 1116)
Years of the Collapse (1117 to 1199)
Years of the Fourth Imperium (1200 to 1300)
Years of the Imperium Eternal (1117 to ????)
Strephon is not assassinated, the Rebellion did not occur, Virus was not released or even developed (though that is not known for certain), and the Fourth Imperium was not founded (obviously).