This game is mix between Master of Orion and Imperium Galactica II. You can be one of many races, each with advantages and disadvantages. The whole game is very customizable, from allowing you to customize galaxy size to designing your own ships.
Pax Imperia II was originally announced as a title to be published by Blizzard. Blizzard eventually dropped Pax Imperia II, though, when it decided it might be in conflict with their other space strategy project, the now-legendary StarCraft. THQ eventually contracted with Heliotrope and released the game in 1997 as Pax Imperia: Eminent Domain.