realm around 1192, with Asen retaining Tarnovo and its region. After Constantine Angelos Doukas was blinded during the rebellion against Isaac II, the Vlachs and the Bulgarians resumed their attacks against the Byzantine Empire. The Emperor dispatched Alexios Gidos and Basil Vatatzes to wage war against the invaders, but their united armies were almost annihilated in the Battle of Arcadiopolis. Peter and Asen conquered new territories in Thrace, including Philippopolis. Isaac II decided to launch a new campaign to recover Thrace himself. While he was mustering his troops at Kypsela, his brother, Alexios, captured and blinded him on 8 April 1195. Alexios III sent envoys to Peter and Asen, proposing to make peace with them. The brothers refused the new emperor's proposal. Asen moved into Byzantine territory and defeated Alexios Aspietes. He captured the Byzantine fortresses along the River Struma leaving Vlach and Bulgarian troops to garrison them. A new Byzantine army, under the command of the Emperor's son-in-law, Isaac Komnenos, launched a counterinvasion. Asen's Vlach, Bulgarian and Cuman troops surrounded the invaders and defeated them near Serres. Komnenos was captured by a Cuman warrior who secretly tried to hold him to ask for a huge ransom from the Emperor. When Asen was informed of Komnenos's capture, he ordered the Cuman to hand over his captive. Death A boyar Ivanko stabbed Asen in 1196, but the motive for this act is uncertain. Choniates, who narrated the events, recorded two versions. According to one account, the captive Isaac Komnenos persuaded Ivanko to kill the Tsar, promising to give his daughter in marriage to him. The second version claims, Ivanko had "clandestine sexual relations with the sister of Asen's wife", but their affair was revealed to Asen. He decided to have his sister-in-law executed for the illicit love affair which insulted his family, but his wife persuaded him to punish Ivanko instead of her sister. Asen ordered Ivanko to come to his tent late at night. Ivanko who had been informed about the tsar's decision came with a sword hidden under his garments. He killed Asen during the meeting. Choniates stated, Ivanko wanted to rule "more justly and equitably" than Asen who had "governed everything by the sword". Stephenson concludes, Choniates' words show that Asen had introduced a "reign of terror", intimidating his subjects with the assistance of Cuman mercenaries. Vásáry, however, says the Byzantines encouraged Ivanko to kill Asen. Ivanko attempted