Manfred, King of Sicily in the context of "Muhammad I al-Mustansir"

Constance II (c. 1249 – (1302-04-09)9 April 1302) was queen regnant of Sicily from September 1282 to November 1285 alongside her husband, King Peter I. She was also queen consort of Aragon from 1276 to 1285. She was a pretender to the Kingdom of Sicily from 1268 to 1282. She was the only daughter of Manfred, King of Sicily, and his first wife, Beatrice of Savoy.

The "Sicilian business" is a historiographical term used to describe the failed attempt by Henry III of England to claim the Kingdom of Sicily for his son Edmund, who had been offered the throne by the papacy. Sicily, established in the twelfth century as a theoretical papal fief, had been ruled by Holy Roman Emperor Frederick II from 1198 until his death in 1250; Pope Innocent IV now sought to install an agreeable sovereign to succeed his longtime adversary. After failed negotiations with Edmund's uncles Richard of Cornwall and Charles of Anjou, the papacy formally offered the throne to the English prince in 1254. For the project, Henry III was tasked with delivering Edmund and armed forces to Sicily to claim it from Manfred, who was serving as regent for Frederick II's grandson Conradin; the papacy was to offer assistance.

A strategic marriage was planned for Edmund; potential brides were the dowager queen of Cyprus or a daughter of Manfred in order to resolve the dispute over the kingdom. Neither union came to fruition, and despite continued attempts to secure support and financing, Henry III's efforts to establish Edmund as the Sicilian monarch faced numerous setbacks. Pope Alexander IV, who had succeeded Innocent IV in 1254, was no longer in a position to effectively finance the project, demanding payment from Henry III as compensation for the papacy's contributions to the campaign. Finding only minimal support from Parliament and faced with the threat of excommunication from Rome, Henry III resorted to extorting money from his domestic clergy in an attempt to pay the debts. The "Sicilian business" became entangled with broader political troubles in England, and the project ultimately collapsed. Pope Urban IV formally revoked the grant of the Kingdom of Sicily to Edmund in 1263 and instead consigned it to Charles of Anjou, who successfully assumed control of the kingdom in 1266.

Beatrice of Savoy (before 4 March 1223 – January 1258) was Marchioness of Saluzzo by marriage to Manfred III, Marquess of Saluzzo, and remarriage to Manfred. She was regent of Saluzzo during the minority of her son in 1244.