However, the most important point of this conversion is that it created an Arab-Berber alliance for the further march of Mohammedanism into Europe. It is said that it was a Berber named Tarik who first crossed the Straits of Gibraltar, and it was after him that the rock took its name, Djebel el Tarik—the Mountain of Tarik. The Arabs and Berbers pressed on through Spain until they were defeated by Charles Martel at Poitiers in 732 and retired into the peninsula. The remains of their grandeur can be seen in the glorious palaces and mosques at Seville, Cordova and Granada. But the Berbers, being of an independent nature, did not readily accept the laws and regulations of the allies. In the tenth century there were a number of insurrections in Algeria, and the Fatimides, or followers of the descendant of Fathma, the daughter of the prophet, succeeded for a period in dominating the country. Unfortunately for them their chief tried to go too far in his independence, and in the twelfth century the Sultan at Cairo launched a punitive expedition composed of the five tribes known as the Hilals. Unlike the expeditions of the seventh century, these invaders came in hordes, bringing with them their flocks and their belongings, and sweeping mercilessly across the country, leaving devastation behind. Arabs and Berbers united to oppose them, but to no avail. Their armies poured over the land like a cloud of locusts. The little that was left of Roman civilization was destroyed, the cultivation disappeared, and North Africa was the desert of over a thousand years before. From this period until the end of the fifteenth century North Africa was given over to pillage. With the exception of the cities of Tunis, Tlemçen and Fez, anarchy seems to have reigned everywhere, and there are no records or history of the period. The Arab had shown his worth; the Arab as an administrator had no qualification; he has not yet proved the contrary. At first it was the Spaniards who took the place as rulers of North Africa. They had gradually driven the Mohammedans out of southern Spain, and during the first ten years of the sixteenth century had occupied the seaports from Oran right down to Bougie, including Algiers. But these conquests did not really interest them as their eyes were turned to the Indies. Moreover, in the meanwhile the brothers Barbarossa were scouring the Mediterranean, and when they were asked to rid Algeria of the Spaniards it did not take them long to do it. But once the deed was accomplished, the Turks refused to leave, and in 1546 took possession of Algiers.