ʿUmar ibn al-Khaṭṭāb (c. 584 – 644), sometimes referred by Muslims as ʿUmar al-Fārūq ("the one who distinguishes between right and wrong") was from the Banu Adi clan of the Quraysh tribe. He was a companion of the Islamic prophet Muhammad and became the second Caliph (634 – 644) following the death of Abu Bakr, the first Caliph. Many of Umar's relatives of the same generation were also Sahaba and his daughter Hafsa bint Umar was a Mother of the Believers. His sons were also important Sahaba.