In the year 22 BBY, the Clone Wars erupted between the Confederacy of Independent Systems and the Galactic Republic, commencing with the First Battle of Geonosis. Around this time, the Confederacy launched an invasion of Onderon, a world situated in the Inner Rim Territories. This occurred after the Confederacy secretly backed a coup that favored the Separatists. Although the Confederacy military was ostensibly "invited" to Onderon by Sanjay Rash, a Separatist figurehead installed via the coup, the reality was an invasion orchestrated by Count Dooku.
During the period of the Clone Wars, Ramsis Dendup, the Onderonian king, chose not to align Onderon with either the Galactic Republic or the Confederacy of Independent Systems. He believed neutrality would shield the planet from the conflict's devastation, given the corruption he perceived in both factions. However, Sanjay Rash, viewing an alliance with the Separatists as crucial for Onderon's future, seized power through dubious means, with some of his subjects considering the king a coward. The Confederacy secretly aided the coup that propelled him into leadership.
Count Dooku designated Rash as king, intending him to be a Separatist puppet. Despite this, Rash formally declared Onderon's secession from the Republic. While the Droid Army was purportedly "invited" to Onderon for security purposes, it was, in truth, an act of invasion. Due to Rash's actions, any overt response from the Republic would be portrayed as aggression. However, the invasion and Rash's appointment ignited an Onderonian Civil War, spearheaded by a resistance movement.