Seeking support for the rebellion, the Sicilians offered the throne to Peter III of Aragon, who claimed the crown on behalf of his wife, Constance of Sicily.

The rising had its origin in the struggle of investiture between the pope and the Hohenstaufen Holy Roman Emperors for control of Italy, especially the Church's private demesne known as the Papal States.

After abortive attempts to enlist England as the champion of the Papacy against Manfred,[6] Urban IV settled on the later Charles I of Naples as his candidate for the Sicilian throne.

Charles regarded his Sicilian territories as a springboard for his Mediterranean ambitions, which included the overthrow of Michael VIII Palaiologos of the Byzantine Empire and the capture of Constantinople.

[7] The unrest was also fomented by Byzantine agents to thwart Charles' projected invasion and by King Peter III of Aragon, Manfred's son-in-law, who saw his wife Constance as rightful heir to the Sicilian throne.

The event takes its name from an insurrection which began at the start of Vespers, the sunset prayer marking the beginning of the night vigil on Easter Monday, 30 March 1282, at the Church of the Holy Spirit just outside Palermo.

The rioters broke into the Dominican and Franciscan convents; and all the foreign friars were dragged out and told to pronounce the word "ciciri", whose sound the French tongue could never accurately reproduce.

But on 28 April it too broke into open revolt under the command of Captain of the People Alaimo da Lentini [it] and, most significantly, the islanders' first act was to set fire to Charles's fleet in the harbor.

They elected leaders, one of whom was Bartholomaeus of Neocastro who was prominent in the unfolding events and would later chronicle much of the revolt in Historia Sicula, an important if sometimes contradictory source of information for historians.

Again significantly, the leaders' next act was to send word, via a Genoese merchant named Alafranco Cassano, to the Emperor Michael advising him that his nemesis Charles had been crippled.

The islanders were hoping for status similar to that enjoyed by Venice, Genoa, Pisa and other cities, which were free to form their own government but morally answerable only to the Pope, who would hold a vague and unstable suzerainty.

Charles' island officials were far removed from his oversight; he did not see the avarice, the rape, theft and murder, nor did he see the high taxes levied against the meager possessions of the peasants, which kept them impoverished, but made no improvement in their lives.

However, when Pope Martin made plain his orders for the Sicilians to accept Charles, Peter promised the islanders that they would enjoy the ancient privileges they had had under the Norman king, William II of Sicily.

[21] With the pope's blessing, the counterattack from Charles was not long in coming; his fleet from the Kingdom of Naples arrived and blockaded the port of Messina and made several attempts to land troops on the island, but all were repulsed.

Years later, in his autobiography, the Byzantine emperor Michael VIII wrote: "Should I dare to claim that I was God's instrument to bring freedom to the Sicilians, then I should only be stating the truth.

"[22] But as Runciman observes, with or without Byzantine gold, it was the proud people of Sicily alone who fought against their armed oppressor; and "However it may have been plotted and prepared, it was that one March evening of the Vespers at Palermo that brought down King Charles' empire.