It is unknown exactly when the conflict began, but it is known that by 22 BBY, it had raged for several decades and become sufficiently violent to draw the attention of the Galactic Republic. In an attempt to diffuse the war, three different Jedi missions were dispatched to negotiate a peace. The final mission was staffed by Jedi Knights Empatojayos Brand, Bultar Swan, and Chellemi Chuovvick. Unable to mediate the dispute, questions surrounding a potential Sepan secession from the Republic became common.
The Sepan Civil War raged on through the Clone Wars and the establishment of the Galactic Empire. As Palpatine's Empire set about restoring order to the galaxy and suppressing the growing Rebellion, the Sepan conflict was forgotten.
Building on their momentum after the victory at Hoth in 3 ABY, Admiral Harkov and a small Imperial fleet was dispatched to the Sepan system to end the war. The Imperial presence was welcomed by the Ripoblus, who saw it as an opportunity to achieve victory over the their Dimok enemies. Harkov, however, was determined to bring both sides to heel. With the help of young Maarek Stele, Harkov's forces drove the two sides together. Representatives from both sides met on Sepan 8 to discuss cooperating to repel the Imperial forces. Their efforts, however, were in vain. Harkov's forces defeated the Sepan forces and their Alliance allies, and ended the Sepan Civil War.
Late in 40 ABY, during the Second Galactic Civil War, old tensions flared up again all across the galaxy. Once again, the Sepan Civil War began between the Ripoblus and the Dimok. It was a high priority of Chief of State Cal Omas to send in Galactic Alliance forces to put an end to the conflict as the Empire had done decades earlier.