BELA IV

born 1206 died May 3, 1270 king of Hungary (1235-70) during whose reign the Mongol invasions left three-quarters of Hungary in ruins. He was the son of Andrew II. Routed on the banks of the Saj River in 1241 by Mongols under Batu Khan, Bla fled to Dalmatia, and for a year the kingdom of Hungary did not exist. So nearly complete was the country's destruction that Hungarians, when referring to total calamity, use the word tatrjrs, meaning Tatar invasion. When the Mongols withdrew because of dynastic troubles, Bla began to reconstruct his realm, a task that occupied the rest of his reign. Particularly difficult was the recovery of western portions of the kingdom seized by Frederick of Austria as the price of the aid he promised against the Mongols but never delivered. Bla defeated Frederick, who died in the battle near the Leitha River on June 15, 1246. Three years earlier Bla had been forced to cede Zadar to Venice, but he retained Split and other Dalmatian provinces. Because of his policy of religious toleration in Bosnia, that province remained quiet for years. Bla fought wars with the new Serbian kingdom, founded by the Nemanja dynasty, and was frequently in conflict with Otakar II over Styria, which ultimately fell to the Bohemians. Bla turned back a second Mongol invasion of Hungary, in 1261, and he resisted the Premyslid dynasty, which had constructed a new Bohemian empire, absorbing territories of the Austrian Babenbergs and threatening Hungary itself. Bla had two sons and seven daughters by his consort, Maria, daughter of the Byzantine emperor of Nicaea, Theodore II Lascaris. Of these children, St. Margaret of Hungary became the best known.