The research is a political study of the position of the Hafsids regarding the Crusader invasion on the countries of the Maghreb for the period between 625 - 668 AH / 12 - 1950 AD, in which the eighth crusade against Tunisia was led by Louis IX, and its theater was the shores of Cartagena, and it was aimed at the occupation of Tunis, the Hafsid capital. I suffered a complete failure due to the violent popular resistance I found. The Eighth Crusade against Tunisia occupies an important place in the history of the Crusades, if it was the last that ended the colonial presence in the Arab lands, and the Crusaders received an unforgettable lesson in it, as they lost their king, Louis IX, the organizer of the campaign and many notables, and they suffered heavy losses due to the resistance they faced. Continuous violent popularity and the siege that hit them until they were hit by starvation, thirst and epidemics. . The research is based on an entry and four main paragraphs: Lewis prepared for the campaign. Al-Mustansir Billahs readiness for confrontation. The clash between the two parties. Fights