第8回十字軍
Clement and James had been encouraged by this, towards the possibility that the Mongols might join the Europeans in a Franco-Mongol alliance against the Muslims. From Viterbo in 1267, they sent a letter, carried by Jayme Alaric de Perpignan. It was responding positively to previous messages from the Mongols, and informed Abaqa of the upcoming Crusade (the Eighth Crusade).