OMAN, CHARLES WILLIAM CHADWICK (1860 —). A British historian, born at Mozufferpore, India. He was educated at Winehester and at New College. Oxford, in 1883 became a fellow of All Souls' College, Oxford, and in 1900 deputy professor of modern history in the uni versity. Among his published works are: A History of Greece (1888) ; .1 Short History of the Byzantine Empire (1892) ; A History of Europe 476-918 (1893), in the "Periods of European History Series"; A Short History of England (1895) : A History of the Art of War in the Mid dle Ages (1898) ; and Seven R0111011. Statesmen (1902).
O'MAR (Ar. ibn a I- Kh b) . The second Mohammedan Caliph. He was born about 581. Before the year 617 he opposed the Prophet. but in that year he was won over to the new faith and became one of its ablest supporters. He was associated with Abu-bekr as one of his principal advisers, and on the death of Abu-bekr in 634 succeeded as Caliph, and pushed on the wars of conquest which had been undertaken by his advice, with increased vigor. The beginning of his reign was signalized by tile victory of Cadesia (635) over the Persians. By 637 Omar had completed the conquest of Syria and Pales tine. In 639 he sent Amru to invade Egypt. In 641 Alexandria fell. and the country passed from
the Greeks to the Saracens. Ile was summoned to Jerusalem in 637 to receive the keys of that city. Barea and Tripoli were next subdued by Ainru. Armenia was overrun in 641. and about the same time the victory of Nehavend brought Persia under the sway of the Arabs. In 644 Omar was assassinated in the mosque of _Medina by a Persian slave from motives of revenge. He lin gered five days after receiving the wound, but re fused to appoint a successor. and named six Nun missioners who were to choose one from among themselves. was buried in the mosque of Me dina, near the Prophet and Alm-hekr, and his tomb is still visited by pilgrims. Omar may be called the organizer of the :Ninhanunedan power. as from a mere sect he raised the followers of Islam to the rank of a conquering nation. and left to his successor an empire. He was the founder of many excellent institutions: he as signed a regular pay to his soldiers, and made some excellent regulations for the more lenient treatment of slaves. He originated the practice of dating from the era of the Hejira (q.v.). See references under CALIPHS :URI 110II AM MEDAN ISM.