Officially the Terran Republican Army in Exile, the Republican Legions ("renegade" is an unofficial "official" appellation) seek to free the Terran Republic of its corrupt leadership and re-establish democratic rule. This has been their goal for over 160 years.
On 15 September, 6681, "over 300,000 Legions", 3,804 Battleship Groups, and their families followed Grand General Douglas Constantin's flagship, the Righteous Fury, into T-space on the long journey across the KessRith Empire to the Commonwealth.
Once accepted into the Commonwealth, the Republican Legions became, in essence, a branch of the Commonwealth Armed Forces, albeit one that is self-governed and which does not respond to the Commonwealth Parliament.