Sunni, or followers of the Sunnah (example) of the Prophet, believed that Muhammad had died without establishing a system for selecting a successor or designating a replacement. After an initial period of uncertainty, the elders or leaders of Medina selected Abu Bakr to be the caliph (successor, deputy). An early convert who had been Muhammad’s close companion and trusted adviser as well as his father-in-law, Abu Bakr was respected for his sagacity and piety. Thus Sunni Muslims adopted the belief that leadership should pass to the most qualified person, not through hereditary succession.