The war began when the Apostolosian Apokine utilized the myth of Apostolos being founded by lost Atlanteans from Earth to rally several other star systems to their cause and launched a campaign of conquest against OriCon and The Diaspora.
Apostolos initially enjoyed significant success by capitalizing on a combination of distrust between Diaspora and OriCon to their advantage and the unique Apostolosian FTL Sail system that permitted Apostolos to send fleets through darkspace, circumventing more heavily fortified systems and launching surprise strikes at worlds deep in Diasporan and OriCon space.
As the war continued, an uneasy ceasefire eventually formed between Oricon and the Diaspora, allowing each nation to focus on fighting Apostolos, and causing the tide of war to slowly turn against the Apostolosians.
As the war worsened, the Apostolosians began development on a superweapon. News of this development lead to further cooperation between the Diaspora and Oricon, who created a joint taskforce to thwart this plot. This taskforce tracked down one of the components of the superweapon on Counterweight. The combined efforts of Addax Dawn and Jace Rethal stopped the Apostolosian plot, but not before the device activated over Counterweight. The resulting explosion caused catastrophic damage to the atmosphere and sea of Counterweight. However as the explosion cleared, a new, pristine planet, now given the name Weight, hung in the sky over Counterweight.
Shortly after this climactic event. Apostolos surrendered, and, as part of the peace talks, was forced to relinquish claims on any planets outside of their home system.