acknowledged his nominal authority. His successor Muhammad I al-Mustansir (1249–1277) proclaimed himself Caliph in 1256 and continued the policies of his father and extended the boundaries of his State by subjugating the central Maghreb, going so far as to impose his overlordship over the Kingdom of Tlemcen, northern Morocco and the Nasrids of Granada Spain. The Hafsids become completely independent in 1264. It was during his reign that the failed Eighth Crusade took place, led by St. Louis. After landing at Carthage, the King died of dysentery in the middle of his army decimated by disease in 1270. Hafsid decline (14th century) In the 14th century the empire underwent a temporary decline. Although the Hafsids succeeded for a time in subjugating the empire of the Abdalwadids of Tlemcen, between 1347 and 1357 they were twice conquered by the Marinids of Morocco. The Abdalwadids however could not defeat the Bedouin; ultimately, the Hafsids were able to regain their empire. During the same period plague epidemics brought to Ifriqiya from Sicily caused a considerable fall in population, further weakening the empire. To stop raids from southern tribes during plague epidemics, the Hafsids turned to the Banu Hilal to protect their rural population. Peak (15th century) During Abd al-Aziz's (1394–1434) reign the country experienced an era of prosperity as he proceeded to further consolidate the kingdom. The beginning of his reign was not easy since the cities of the south revolted against him. However, the new sultan quickly regained their control: he reoccupied Tozeur (1404), Gafsa (1401), and Biskra (1402), and tribal power of the regions of Constantine and Bugia (1397–1402), and appointed governors of these regions to be elected, generally libertarian officers. He also intervened against his western and eastern neighbors by annexing Tripoli (1401), Algiers (1410–1411) and by defeating the Zayyanid dynasty in 1424 and replacing it with a pro-Hafsid ruler which would later revolt against him in 1428 and 1431. In 1429, the Hafsids attacked the island of Malta, and took 3000 slaves although they did not conquer the island. Kaid Ridavan was the military leader during the attack. The profits were used for a great building programme and to support art and culture. However, piracy also provoked retaliation from the Christians, which several times launched attacks and crusades against Hafsid coastal cities such as the Barbary crusade (1390), the Bona crusade (1399) and the capture of Djerba in 1423.