rode to Hungary expecting to negotiate the agreements that normally accompanied such an alliance. However, Béla IV rebuffed him, and he, greatly angered also by his son, returned to Chernigov and disowned Rostislav. Acting as his father-in-law's agent, Rostislav made two unsuccessful attacks of Halych. Sometime in 1244, he led a Hungarian force against Przemyśl; Daniil Romanovich, however, marshaled his troops and routed the attackers making Rostislav flee to Hungary. In the following year, Rostislav recruited many Hungarians and Poles and launched an attack against Jarosław north of Przemyśl; on August 17, 1245, his uncle, with Cuman help, annihilated the enemy, and Rostislav had to flee again to Hungary. After his defeat, Rostislav never returned to Halych. Ban of Slavonia and Duke of Macsó Rostislav received land grants from his father-in-law in Hungary, and thus he became the lord of the royal possessions of Bereg and the Castle of Füzér. He was mentioned among the dignitaries of Béla IV as Ban of Slavonia in 1247, and from 1254 onward he was mentioned as the Duke of Macsó (in Latin, dux de Macho). The Banate of Macsó originally centered around the river Kolubara, but later it also included Belgrade (in Hungarian, Nándorfehérvár) and by 1256, if not earlier, Braničevo (in Hungarian, Barancs). In 1255, a peace between the Kingdom of Hungary and the Bulgarian Empire was sealed, and Tsar Michael of Bulgaria married Rostislav's daughter. In 1256, Rostislav mediated a peace between his son-in-law and Emperor Theodore II of Nicaea. His struggle for Bulgaria Late in 1256 (probably in December), a group of boyars, who had decided to kill Tsar Michael and replace him with his first cousin, Koloman, attacked the former, who died soon afterwards from his wounds. To further his claims, Koloman II forcibly married Michael's widow, the daughter of Rostislav, but he could not consolidate power and was killed almost immediately. To protect his daughter, Rostislav now, early in 1257, invaded Bulgaria; it seems he was using her as an excuse to acquire the Bulgarian throne for himself. Rostislav appeared at the gates of Tărnovo and recovered his daughter; though it is sometimes stated that he briefly obtained Tărnovo, but it seems that he probably never actually gained possession of the city. Having failed to take Tărnovo, Rostislav retreated to Vidin where he established himself, taking the title of Tsar of Bulgaria, and the Hungarians recognized him with