750
After the defeat of his army in the Battle of the Zab the last Umayyad Caliph, Marwan II, is overthrown and killed. Al-Saffah is proclaimed the first Abbasid Caliph. The capital of the Caliphate will later moved from Damascus to Baghdad, within the territory of the former Persian Empire; this transfer will prove to be a momentous event for Baghdad, which develops into a centre of international trade and culture.