Umar

Umar or Omar , c.581-644, 2d caliph (see caliphate ). At first hostile to Islam, he was converted by 618, becoming an adviser to Muhammad. He succeeded Abu Bakr as caliph without opposition in 634. In his reign Islam became an imperial power. The Muslim generals pushed conquests far and wide—into Syria, Egypt, and the Persian Empire. Umar also laid the administrative base of the empire, creating the office of kadi and establishing fixed taxes. He reopened the canals of Mesopotamia and the waterway from the Nile to the Red Sea. Umar was assassinated by a foreign slave. He had appointed a group to select his successor, and the choice fell on Uthman .

Omar (active c.581–644) ( Umar) Second Caliph, or ruler, of Islam. He was converted to Islam in 618, and became a counsellor of Muhammad. In 632, he chose the first caliph, Abu Bakr, and succeeded him in 634. Under his rule, Islam spread by conquest into Syria, Egypt, and Iran, and the foundations of an administrative empire were laid.

Umar ibn al-Khattab (c.581–644 AD) Second CALIPH of Islam (634–44). He presided over the first major wave of ARAB CONQUESTS, which were the work of great captains such as Khalid ibn al-Walid. Hostile at first to MUHAMMAD, he became an ardent convert. The bond between them was strengthened by Muhammad's marriage to Umar's daughter Hafsa. His genius was administrative rather than military and his achievements included systematizing the rule of his vast territories, establishing the Islamic calendar, organizing state pensions, and upholding justice.