Traditions of the life of Muhammad and the early history of Islam were passed down mostly orally for more than a hundred years after Muhammad's death in AD 632. Muslim historians say that Caliph Uthman ibn Affan (the third khalifa (caliph) of the Rashidun Caliphate, or third successor of Muhammad, who had formerly been Muhammad's secretary), is generally believed to urge Muslims to record the hadith just as Muhammad suggested to some of his followers to write down his words and actions.