services to the Roman empire were Acknowledged by the senate who decreed him very high honours; Honorius sent him as his ambassador to the Huns; and he lived afterwards at the court of Theodosius in Byzantium. The work by which he is known as a writer is entitled Ἱστορικοὶ Λόγοι, in twenty-two books, containing a history of the western empire from 407 till October, 425. It is lost; but an abridgment has been preserved by Photius, which was published by Niebuhr at Bonn, 1829, 8vo.—S. D.
OLYMPIODORUS, a Greek monk and deacon of Alexandria belonging probably to the sixth century. He wrote a commentary on Ecclesiastes, which was published in Greek and Latin in the Auctarium Ducæanum Bib. Patr., 1624. The Catena on Job ascribed to him was probably Nicetas'. Commentaries on other Old Testament books (Jeremiah, Ezra) have been assigned to him without much evidence.—S. D.
OLYMPIODORUS, a philosopher of the new Platonic school of Alexandria, who belonged to the sixth century and the reign of Justinian. He was partly contemporary with Damascius, to whose philosophy he seems to have been partial. His works are in the form of scholia or notes, which were taken from his lectures by pupils, and are divided into πράξεις or lessons. These contain a life of Plato; notes on the Gorgias, Philebus, Phædo, and Alcibiades I.; and a work against Strato still in MS. A good deal of light is thrown upon Plato and his works by these scholia, which have been repeatedly published. The author has the merit of clearness and distinctness, and his style is pure for the time. Olympiodorus seems to have been well acquainted with the works of the philosophers antecedent to his time, and often quotes them. He was evidently a man of intellectual ability, an acute thinker, and good expositor.—S. D.
OLYMPIODORUS, an Aristotelian philosopher of Alexandria belonging to the latter part of the sixth century. He wrote a commentary on the Meteorologica of Aristotle, which was published by the Aldi at Venice, 1551. He followed Ammonius and Proclus.—S. D.
OMAR I. (Abu Haffsah Ibn-al-Khattàb), the second khalif of the mussulmans, was the third cousin of Abdallah, the father of Mahomet. He was at first the inveterate enemy of the prophet, and set out one day with the intention of murdering him, but was diverted from his purpose and converted to the new faith by the accidental perusal of the twentieth chapter of the Koran. He immediately became one of Mahomet's most zealous adherents, and by his courage and ability contributed greatly to the success of his cause. He occupied a foremost place in the regard of his leader, who ultimately married his daughter, Haffsah. "If God should wish," said the prophet, "to send a second messenger to this world, his choice would undoubtedly fall on Omar." At the death of Mahomet, Omar displayed his self-sacrificing spirit by promptly waiving his claims to the khalifate, when a dangerous quarrel seemed imminent between his supporters and those of Abù Bekhr, and he even submissively accepted the office of chamberlain to his rival. On the death of Abù in 634, Omar was appointed his successor in compliance with his express request. "I have no occasion for the place," said Omar. "But the place has occasion for you," replied the dying khalif. The wisdom of this choice was fully vindicated by the manner in which the new "commander of the faithful" discharged the duties of his office. He speedily communicated his energy and activity to his subordinates, and prepared his soldiers by severe discipline, and by inspiring them with his own high-toned fanaticism, for the religious wars in which he employed them. The first act of his administration was to remove from the command of the Syrian army the celebrated Khaled Ibn-Walid, surnamed "The Sword of God," who had rendered himself most obnoxious by his rapacity and cruelty. His successor, Abù-Obeydah, zealously prosecuted the conquest of Syria: took Damascus, its capital, in September, 635; reduced Emesa, Hamah, and Kennesrin; and in the following year defeated the Greeks in the bloody battle of Yermúk. Jerusalem was next attacked, and after a protracted and strenuous defence the patriarch Sophronius, who commanded the garrison, agreed to surrender, but only to the khalif himself. Omar accordingly hastened from Medina to Jerusalem, meanly equipped and attended by a scanty suite; and having arranged the terms of the capitulation, made his triumphal entry into the holy city about the middle of the year 637. He caused a magnificent mosque to be erected on the site of Solomon's temple, which still remains an object of great veneration to the mussulmans. The capture of Jerusalem was followed by the reduction of all the principal cities of Palestine, as well as of Laodicea, Antioch, Aleppo, and Baalbec. Persia was next invaded. A powerful Persian army was defeated at Kádesiyyah, and its commander, the famous Rustam, killed; the city of Rufah or Bassora was founded near the Euphrates, and Madáyin, the capital of Yezdijerd the Persian king, taken in 637. The conquest of Egypt was then undertaken, and completed by the capture of Alexandria in 640. The conquerors unfortunately tarnished their laurels by destroying the famous library founded by Ptolemy Philadelphus. The Mahometan general, Amru-Ibn-al-Ass having applied to the khalif to know his pleasure respecting the disposal of this collection, received from Omar the well-known reply, "If the books agree with the book of God (Koran) they are useless; if they disagree they are pernicious; let them therefore be destroyed." The conquest of Egypt was followed by that of part of Africa. Armenia was subdued in 641 and Khorassan in 642, and the subjection of Persia was completed in the same year, by the decisive victory of Nehavend, in which Firuz, the Persian general, fell, and the king himself was driven from the country and compelled to seek an asylum among the Turks. But the career of Omar was now drawing to a close. His severity towards the vanquished who refused to embrace the Mahometan faith, and not less his inexorable administration of justice, raised up numerous enemies against him, and several unsuccessful attempts were made upon his life. At length, in November, 642, he was assassinated while performing his devotions in the mosque at Medina by a Persian slave named Abù Lùlù Firùz, whose deadly enmity the khalif had incurred by his refusal to relieve him from a portion of the tribute which, in conformity with the Mahometan custom, he was obliged to pay to his master for the free exercise of his religion. Omar was in his sixty-fifth year at the time of his death. He was one of the most upright, zealous, and able of the rulers of the mussulmans, among one sect of whom his memory is still held in the highest veneration. He was especially renowned for his strict and impartial administration of justice, without respect of persons. He lived in primitive simplicity, on a small pittance which he earned by manufacturing leather belts. His only food was barley-bread and dates, his drink water, and his garb an old tattered gown, and he often slept under a wayside tree or on the steps of the great mosque. Much of his time was spent in praying and preaching at the tomb of the prophet, and during his khalifate he performed nine times the pilgrimage to Mecca. It was a common saying, that the staff of Omar was more dreaded than the sword of his successors. It was in his reign that several of the best Mahometan institutions had their origin. He commenced the custom of paying the troops, and pensioning officers out of the public revenue. It was he also who established a police force for the protection of the citizens during the night. The practice, now universal in Mahometan countries, of computing time from the Hegira, or flight of Mahomet, originated in his reign.—J. T.
OMAYAH or OMMIAH, the son of Abdal Shem, a prince who ruled the Arab tribe of Koreish, the same to which Mahomet belonged. He was the nephew of the prophet's great-grandfather Hashem, and lived in the sixth century after Christ. He is regarded as the founder of the dynasty of the Ommiade khalifs, who occupied the supreme dignity about ninety years. His grandson, Mohawiyah Ebn Abu Sofian, or Abu Saifan was the successor of the khalif Hasan in a.h. 41. Mohawiyah reigned nineteen years and two months, and was succeeded by his son Yezid, who reigned three years and eight months. After Yezid, Mohawiyah II. was proclaimed, but deposed in a few weeks. Merwan followed, and was poisoned in less than a year. The remaining khalifs of the dynasty were Abdalmelek, Walid, Soliman, Omar, Yezid II., Hashem, Walid II., Yezid III., Ibrahim, and Merwan II.; after whom the Abassides rose to power.—B. H. C.
O'MEARA, Barry Edward, surgeon to Napoleon Bonaparte at St. Helena, was born in 1786, and entered the army as assistant-surgeon in 1804. In 1808 he was cashiered for having acted as second in a duel between two officers at Messina in Sicily. He then became a naval surgeon, and was serving on board the Bellerophon under Captain Maitland, when Napoleon was received on board that vessel in 1815. O'Meara's knowledge of Italian made him serviceable in the intercourse between the English officials and the fallen emperor, with whom he was
