Asen and Peter (who was still known as Theodor at that time) went to see the Byzantine Emperor, Isaac II Angelos, in Thrace in 1185, to demand an estate in the Balkan Mountains. After the Emperor had refused them, the brothers persuaded their compatriots to rise up against the Byzantine Empire. Peter was crowned emperor before the end of the year. After Isaac II defeated them in early 1186, Asen and Peter fled over the Danube, but they returned in the autumn, accompanied by Cuman reinforcements. They captured Paristrion and began pillaging the nearby Byzantine territories.