Alexius IV

When Alexius III overthrew Isaac II in a coup in 1195, Alexius IV escaped from the custody of his uncle and fled to his brother-in-law Philip of Swabia, who was married to his sister Irene. While there he met Boniface of Montferrat, Philip's cousin, who had been chosen to lead the Fourth Crusade, but had temporarily left the Crusade during the siege of Zara to visit Philip. Boniface and Alexius discussed diverting the Crusade to Constantinople so that Alexius and his father could be restored to the throne. In return, Alexius would give them Byzantine soldiers to help fight the Crusade, as well as money to pay off the Crusaders' debt to the Venetians. The Venetians were in favour of this plan when they learned of it, and in 1202 the fleet arrived at Constantinople. They paraded Alexius outside the walls, but the citizens were apathetic, as Alexius III, though a usurper and illegitimate in the eyes of the westerners, was an acceptable emperor for the Byzantines.

In 1203 the Crusaders launched an assault on the city, and Alexius III immediately fled. The next morning the Crusaders were surprised to find that the citizens had released Isaac from prisoner and re-crowned him as emperor, despite the fact that he had been blinded to make him ineligible to rule. The Crusaders could not accept this, and forced Isaac to proclaim Alexius IV co-emperor. Despite Alexius' grand promises, Isaac, the more experienced and practical of the two, knew that the Crusaders' debt could never be repaid from the imperial treasury. In any case Isaac soon died, and Alexius came under the control of Alexius Murtzouphlos, an influential general. While Alexius IV delayed payment to the Crusaders, Murtzouphlos gained support among the nobles and citizens, and in 1204 overthrew Alexius. He took power for himself as Alexius V and shortley afterwards had Alexius IV strangled to death.