The Byzantines captured Ivanko and occupied his lands in 1200. Kaloyan and his Cuman allies launched a new campaign against Byzantine territories in March 1201. He destroyed Constantia (now Simeonovgrad in Bulgaria) and captured Varna. He also supported the rebellion of Dobromir Chrysos and Manuel Kamytzes against Alexios III, but they were both defeated. Roman Mstislavich, prince of Halych and Volhynia, invaded the Cumans' territories, forcing them to return to their homeland in 1201. After the Cuman's retreat, Kaloyan concluded a peace treaty with Alexios III and withdrew his troops from Thrace in late 1201 or in 1202. According to Kaloyan's letter to the Pope, Alexios III was also willing to send an imperial crown to him and to acknowledge the autocaphalous (or autonomous) status of the Bulgarian Church.