Era-2 starts with the birth of Potus Clarke, who would go on to be the god-Emperor of the Holy Empire of Man.  The imperial calendar starts with Clarke's birth, and denotes years as Year of the Emperor (abbreviated YE).  Where dates overlap with Era-1, the Galactic Standard Calendar (GSC) date is also noted. 

The Holy Empire of Man

The Holy Empire of Man (HEM) was the dominant faction of Era-2, conquering most of the galaxy, and ruling with an iron fist.  Founded under the aegis of the Church of God, with its capitol on Gabriel, the Empire was marked by its militarism, fanatical devotion to (and eventually worship of) the Emperor, and strict hierarchical society.  Those who stood in opposition were put down quickly and decisively.

Timeline

YE 0:  The birth of Potus Clarke (GSC 915)

YE 23:  First Contact between the Planetary League and the Empire of 1,000,000 Suns (GSC 938)

YE 43:  Holy Empire of Man founded, coronation of Potus Clarke(GSC 958)

YE 43:  Start of the Great Reckoning (GSC 958)

YE 147:  The Fall of Earth (GSC 1062)

YE 613:  the Ascent from the Flesh (Emperor Clarke's body is henceforth wholly cybernetic)

YE 812:  Start of the War of the Empires

YE 10433:  End of the War of the Empires (Fall of the E1MS)

YE 30516:  The War of the Gods begins with the return of Troniac.

YE 51245:  End of the War of the Gods (Final defeat of Troniac)

YE 65248:  Start of the War of Galactic Unification

YE 70794:  Defeat of the Emperor, end of Era-2