In 719, former emperor Anastasius headed a revolt against Leo III, receiving considerable Bulgar support. The rebel forces advanced on Constantinople. The Bulgarians betrayed Anastasius, leading to his defeat. The enterprise failed, and Anastasius fell into Leo's hands and was put to death by his orders on 1 June. He was killed along with other conspirators including Niketas Xylinitas and the archbishop of Thessaloniki.