Main article: Sol Empire
On February 25, 437 PT the Sol Empire's predecessor, the Interplanetary Federation of Sol, fell into civil war. Growing unrest between the planetary and orbital colonies was fueled by a group calling themselves the Sons of Unity, led by Titus Young, Sr. This group united the outer colonies that felt they were under-represented and under-valued in the Federation's central government in what first began as mostly peaceful, open protests, but quickly turned to open warfare as Federation officials tried to suppress and silence the protestors. Empire records show that the first instance of fighting broke out when Federation police opened fire on a group of unarmed protestors in what became known as the Atlas Massacre, named after the orbital colony station Atlas where the event took place.
The outer colonies responded with outcries, and the Sons of Unity began arming themselves and the colonists. What started out as a series of protests turned into a full out rebellion, with the Sons of Unity and Titus Young Sr at the fore-front. The civil war lasted a full year, with the core colonies being overrun and overwhelmed by the growing support for the Sons of Unity and their mission to 're-unite humanity under a fair and just nation.' On February 8, 438 PT, with the IFS leadership on Mars overthrown, Titus Young Sr addressed the people of the IFS, declaring the end of the Federation and the dawning of a new nation: The Sol Empire. An empire which he, himself, would lead through peace and prosperity, just as he had led the Sons of Unity and outer colonies to make this new nation possible.
Every year since, February 8 has been celebrated within the Empire as 'Reunificiation Day'.