ALP ARSLAN  , or AxAN, MAHOMMED BEN DA'UD (1029-1072), the second sultan of the dynasty of Seljuk, in Persia, and great-grandson of Seljuk, the founder of the dynasty, was born in the year A.D . 1029 (421 of the Hegira) . He assumed the name of Mahommed when he embraced the Mussulman faith; and on account of his military prowess he obtained the surname Alp Arslan, which signifies " a valiant lion." He succeeded his father Da'ud as ruler of Khorasan in 1059, and his uncle Togrul Bey as sultan of Oran in 1063, and thus became sole monarch of Persia from the river Oxus to the Tigris . In consolidating his empire and subduing contending factions he was ably assisted by Nizam ul-Mulk, his vizier, one of the most eminent statesmen in early Mahommedan history . Peace and security being established in his dominions, he convoked an assembly of the states and declared his son Malik Shah his heir and successor . With the hope of acquiring immense booty in the rich church of St Basil in Caesarea, the capital of Cappadocia, he placed himself at the head of the Turkish cavalry, crossed the Euphrates and entered and plundered that city . He then marched into Armenia and Georgia, which, in 1064, he finally subdued . In 1o68 Alp Arslan invaded the Roman empire . The emperor Romanus Diogenes, assuming the command in person, met the invaders in Cilicia . In three arduous campaigns, the two first of which were conducted by the emperor himself while the third was directed by Manuel Comnenus, the Turks were defeated in detail and finally (1070) driven across the Euphrates . In 1071 Romanus again took the field and advanced with 1oo,000 men, including a contingent of the Turkish tribe of the Uzes and of the French and Normans, under Ursel of Baliol, into Armenia . At Manzikert, on the Murad Tchai, north of Lake Van, he was met by Alp Arslan; and the sultan having proposed terms of peace, which were scornfully rejected by the emperor, a battle took place in which the Greeks, after a terrible slaughter, were totally routed, a result due mainly to the rapid tactics of the Turkish cavalry .

Romanus was taken prisoner and conducted into the presence of Alp Arslan, who treated him with generosity, and terms of peace having been agreed to, dismissed him, loaded with presents and respectfully attended by a military guard . The dominion of Alp Arslan now extended over the fairest

part of Asia; 1200 princes or sons of princes surrounded his throne and 200,000 warriors were at his command . He now prepared to march to the conquest of Turkestan, the original seat of his ancestors . With a powerful army he advanced to the banks of the Oxus . Before he could pass the river with safety it was necessary to subdue certain fortresses, one of which was for several days vigorously defended by the governor, Yussuf Kothual, a Kharizmian . He was, however, obliged to surrender and was carried a prisoner before the sultan, who condemned him to a cruel death . Yussuf, in desperation, drew his dagger and rushed upon the sultan . Alp Arslan, the most skilful archer of his day, motioned to his guards not to interfere and drew his bow, but his foot slipped, the arrow glanced aside and he received the assassin's dagger in his breast . The wound proved mortal, and Alp Arslan expired a few hours after he received it, on the 15th of December 1072 . See Gibbon, Decline and Fall of the Roman Empire, edited by J . B . Bury (1898), vi. pp .

235 et seq., and authorities there cited . ALPENA, a city and the

county seat of Alpena county, Michigan, U.S.A., on Thunder Bay, a small arm of Lake Huron, at the mouth of Thunder Bay river, in the N.E. part of the lower peninsula . Pop . (189o) 11,283; (1900) 11,802, of whom 4193 were foreign-born; (1910 census) 12,706 . It is served by the Detroit & Mackinac railway and by steamboat lines to Detroit and other ports . The city is built on sandy ground on both sides of the river and has a good harbour, which has been considerably improved by the Federal government; in 1907 the maximum draft that could be carried over the shallowest part of the channel was 14 ft . There is good farming land in the vicinity and Alpena has lumber and shingle mills, pulp works, Portland cement manufactories and tanneries; in 1905 the city's factory products were valued at $2,905,263 . In 1906 the commerce of the port, chiefly in lumber, cement, coal, cedar posts and ties, fodder and general merchandise, was valued at $3,018,894 . Alpena occupies the site of an Indian burying-ground . A trading-post was established here in 1835, but the permanent settlement dates from 1858; in 1871 Alpena was chartered as a city .