After the death of "al-Mahdi", Jesus will assume leadership. This is a time associated in Islamic narrative with universal peace and justice. Islamic texts also allude to the appearance of "Ya'juj and Ma'juj" (known also as Gog and Magog), ancient tribes which will disperse and cause disturbance on earth. God, in response to Jesus' prayers, will kill them by sending a type of worm in the napes of their necks, and send large birds to carry and clear their corpses from the land. Jesus' rule is said to be around forty years, after which he will die. Muslims will then perform the funeral prayer for him and then bury him in the city of Medina in a grave left vacant beside Muhammad, Abu Bakr, and Umar (companions of Muhammad and the first and second Sunni caliphs ("Rashidun") respectively.