The Army of Southern Parthenia was the largest of several field armies raised by Grand Duke Geoffrey during his rebellion against King Avram of Detina. It was charged with the protection of Nonesuch, Parthenia, the capital of Geoffrey's "kingdom". Initially commanded by Joseph the Gamecock, Duke Edward of Arlington took command of the army after Joseph's wounding during the Southron attack up the Henry River. Under Edward, the Army won a number of tactical victories against larger loyal forces, such as the victory over Fighting Joseph at Viziersville. However, the Army was defeated for the first time at Essoville by the Mead-swiller, and the following year was bested by Marshal Bart during the Pierreville Campaign.
The Army of Southern Parthenia is based on the Army of Northern Virginia.