Hazrat Umar ibn al-Khattab (RA) belonged to the Banu Adiyy (Adi) clan of the Quraish tribe. This is the same answer as question 98. He was initially one of the fiercest opponents of Islam but became one of its strongest supporters after his conversion. His justice, administrative skills, and military conquests during his 10-year caliphate (634-644 CE) expanded the Islamic empire to include Persia, Jerusalem, Egypt, and parts of the Byzantine Empire.