 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.Uthman's labours were cut short by his assassination, at the hands of aggrieved soldiers, in 656.No sources survive directly from this period so we are dependent on what later writers tell us about this period.