ASEN or ASSEN, the name of the greatest mediaeval Bulgarian dynasty. Its real surname was apparently Belgun. The family is said to have been of Vlach origin ; Nicetas states that a prisoner spoke to Asen in Vlach, "which was also his own lan guage"; the Crusader chroniclers (e.g., Villehardouin, Conquete, c. xliii., sect. 202) state that Kalojan was a Vlach, and refer to him as "king of the Vlachs and Bulgars," and Pope Innocent III., in his correspondence with Kalojan, refers to him as "descended from an ancient race of the city of Rome." The Asens also claimed descent from the old (Slavonic) dynasty of the Sis manovtsi, of Western Bulgaria.
Two brothers, Peter and Ivan Asen Belgun, were in 1185 boyars of the twin rock-fortresses of Tsarevitsa and Trapesitsa at Trnovo, on the north edge of the Balkans. In that year, on their request for a more independent position being refused by Byzan tium, they called together the neighbouring Vlachs and Bulgars, proclaimed independence from Greece, and gave the signal for a general rising. Defeated at first, they allied themselves with the Cumans and soon freed almost all North Bulgaria. In 1 187 they concluded an armistice with the emperor Isaac Angelos, to whom they sent their younger brother, Kalojan, as hostage; but on Kalojan's escaping they renewed hostilities and defeated the emperor completely near Stara Zagora. About 1196 Ivan Asen died, and Peter was murdered by his own boyars shortly after. Kalojan was then proclaimed tsar of all the Bulgars and Vlachs. This very able but cruel king, also known as Joanitsa, and (scur rilously) as Skulojan or "Whelp-John," completed the conquest of North Bulgaria in 1201, and opened up negotiations with Pope Innocent III., in the hope of obtaining from him the title of emperor. The pope sent a cardinal to crown him, but only as king, in 1204; but in the remarkable correspondence between them he declared to Kalojan that he "extolled him above all other Christian rulers," and "loved him so much that he thought only of his interests and glory," while the Crusaders, who captured Constantinople in 1204, were very curtly ordered to make their peace with the pope's new friend. The Latin emperor Baldwin, however, when offered an alliance by Kalojan, ordered him to approach the Crusaders, as a slave approaches his master, to renounce the throne he had usurped and return to the status of a slave. The incensed Bulgarian, after defeating the Crusaders at Adrianople (1205), captured and perhaps murdered Baldwin (see BALDWIN I.) . After ravaging Thrace with his Cumans for two years, Kalojan was murdered, while besieging Salonika, by the leader of his Cuman forces, perhaps at the instigation of his own wife, who was a Cuman.
The throne was now seized by his nephew Boril, who, however, proved unsuccessful and unpopular, and was dethroned and blinded in 1218 by his cousin Ivan Asen II., son of Ivan Asen I. Ivan Asen II. was one of the greatest of Balkan sovereigns. He was a brilliant soldier and his humanity and piety were admitted by the Greeks themselves. In 1230, by defeating Theodore, despot of Epirus, at Klokotnitsa, he added to his realms Mace donia, Epirus and much of Albania; and soon after he conquered most of Serbia. He now assumed the title of "tsar of the Greeks and Bulgars," but his ambition to wear the imperial crown in Constantinople was never fulfilled. He had been virtually protec tor of the weak Frank empire, and his daughter Helen had been betrothed to Baldwin II.; but the contract was dissolved by the pope, who excommunicated Asen, and his siege of Constantinople in 1225-26, in alliance with the emperor of Nicaea, was abandoned on account of an invasion of North Bulgaria by the Mongols.
Ivan Asen II. died in 1241. An interesting inscription in the church of the Forty Martyrs at Trnovo, his capital, records his exploits. He was succeeded by his sons Caliman I. (1241-46) and Michael (1246-57), the latter under the regency of his mother, the Greek Irene. Their sister Tamara married the Byzantine emperor Michael Palaeologos. Caliman II. (1257-58) was a cousin of the above and the last of the male line of Asen. Mitsa, nephew of Caliman and Michael, seized the throne in 1262, but was ex pelled, fled to Constantinople, and was settled by the emperor on an estate near Troy. His son, Ivan III., married Irene, daugh ter of Michael Palaeologos, and was crowned at Trnovo in 1279, but, defeated by his rival, the swine-herd Ivailo, he fled from Bulgaria in 1280.
See under BULGARIA, CRUSADES, and ROMAN EMPIRE, LATER ; also Du Cange, Familiae Dalmaticae, pp. and Gesta Innocent III., cc. 66-82, pp. 513-25, for the correspondence between Kalojan and the pope. (C. A. M.)