Throughout Islamic history, one of the uniting aspects of the Muslim world was the caliphate. After the death of Prophet Muhammad, his close companion, Abu Bakr, was elected as the first khalifah, or caliph, of the Muslim community. His job as leader combined political power over the Muslim state as well as spiritual guidance for Muslims. It became a hereditary position, occupied at first by the Umayyad family, and later by the Abbasids. In 1517, the caliphate was transferred to the Ottoman family, who ruled the largest and most powerful empire in the world in the 1500s. Read more