Demetrius of Thessaloniki
The brothers knew that the collection of an extraordinary tax, which had been levied in the autumn of 1185, angered the population, especially in the region of Anchialos (now Pomorie in Bulgaria). However, they could not provoke the discontented people into rebellion initially because their compatriots looked "askance at the magnitude of the undertaking", according to Choniates. Theodor-Peter and Asen decided to take advantage of the Bulgarians and Vlachs' devotion to the cult of the martyr saint Demetrius of Thessaloniki to persuade them to rise up against the Byzantine rule.