Uthman gave him permission after considering it in the Majlis al Shura. A force of 10,000 soldiers was sent as reinforcement. The Rashidun army assembled in Barqa in Cyrenaica, and from there they marched west, captured Tripoli, and then advanced to Sufetula, Gregory's capital. In the ensuing battle, the Exarchate was defeated and Gregory was killed due to the superior tactics of Abdullah ibn Zubayr. Afterwards, the people of North Africa sued for peace, agreeing to pay an annual tribute. Instead of annexing North Africa, the Muslims preferred to make North Africa a vassal state. When the stipulated amount of the tribute was paid, the Muslim forces withdrew to Barqa. Following the First Fitna, the first Islamic civil war, Muslim forces withdrew from north Africa to Egypt. The Ummayad Caliphate would later re-invade North Africa in 664.