First Expansion

Confusingly, the First Expansion wasn't actually a first expansion: that would've been a title awarded to whichever pioneers first took off for the sake of pre-Schism humanity's surveying efforts. It instead references a golden age of exploration and co-operation before the nations of Alpha Sector made "full contact" and established the colonial boundaries used today.

The First Expansion occured roughly 3,000 years before the Common Era.