Justinian II approached Tervel of Bulgaria who agreed to provide all the military assistance necessary for Justinian to regain his throne in exchange for financial considerations, the award of a Caesar's crown, and the hand of Justinian's daughter, Anastasia, in marriage. In spring 705, with an army of 15,000 Bulgar and Slav horsemen, Justinian appeared before the walls of Constantinople. For three days, Justinian tried to convince the citizens of Constantinople to open the gates, but to no avail. Unable to take the city by force, he and some companions entered through an unused water conduit under the walls of the city, roused their supporters, and seized control of the city in a midnight coup d'état. Justinian once more ascended the throne, breaking the tradition preventing the mutilated from Imperial rule. After tracking down his predecessors, he had his rivals Leontius and Tiberius brought before him in chains in the Hippodrome. There, before a jeering populace, Justinian, now wearing a golden nasal prosthesis, placed his feet on the necks of Tiberius and Leontius in a symbolic gesture of subjugation before ordering their execution by beheading, followed by many of their partisans, as well as deposing, blinding and exiling Patriarch Kallinikos I of Constantinople to Rome.