The Eighth Crusade took place in 1270 CE. It was led by Louis IX of France, in response to attacks by the Mamluk sultan Baibars on the remanants of the Crusader states. By 1265 Baibars had conquered Nazareth and Toron, and the nominal king of Jerusalem, Hugh III of Cyprus, had been obliged to go to Acre in order to defend the city.
Louis originally mooted the crusade in 1267, but he got little support. His brother, Charles of Anjou, proposed an attack on Tunis, to persuade the sultan to convert to Christianity, as a precursor to attacking Egypt, whch the crusader powers had twice attacked and been beaten back. In July 1270 Louis and an army landed, and promptly fell sick due to plague and poisonous drinking water. Charles arrived in August and within days Louis had died, and his young son, Philip IIII, had been declared king in his place.
Charles pressed the attack until October, by which time Edward of England had arrived to join the campaign. By agreement with the sultan of Tunis, the attack was then ceased, in return for trade rights and liberty for monks and priests to live in the city, and Charles returned to France, to rule for Philip. Edward, meanwhile, proceeded on to Syria, on the Ninth and last Crusade.