The Solar Alliance was founded in 2174 for common defense purposes among its main member-worlds Earth, Tarnak, and Leptax, as well as a number of other worlds.  The alliance quickly began to strengthen its laws and drew more and more into a single state.  Shared technology and a single treasury were the results of the Allied Advisory Congress at Pryll in 2185, little more than a decade after its foundation.  Treaties and trade agreements with the Union of Independent Planets were signed, opening new markets to the merchants of the alliance.  In 2198, the Solar Alliance was contacted by the similar Tauria-Crylix Alliance and given warnings of hostile races to the galactic south. 

In 2200, the first skirmishes with the Southern Alliance began and the allied leadership quickly pushed more resources into shipbuilding and weapons development.  It was soon determined that the Southern Alliance, Gatraxia in particular, was better armed and battle-tested by frequent border wars with the other governments, and that success depended on a quick acceleration of the stellar military industry.  The Gatraxian invasion of Trader’s World in 2203 proved to be the turning point, in which Allied starships were first capable of repulsing numerous attacks, and then forcing the complete withdrawal of Gatraxian forces from Allied territory. 

Friendly gestures by the Tauria-Crylix Alliance led to the arrival of Taurian delegates at the Allied Advisory Congress of 2341.  Military information regarding the Southern Alliance was exchanged as well as technical readouts of Gatraxian starships and war materials.  In 2264, a move was made at Pryll to combine the two alliances for mutual defense, trade, and legislative purposes.  The Solar Alliance was abolished in 2277, at the charter of the Interstellar Organization of United Imperial Worlds.