When their amirs crossed the Straits it was to lead a jehad against the Christians and to return to their capital, Marrakesh.
Nominally part of the sultanate of Tlemcen, Algiers had a large measure of independence under amirs of its own, Oran being the chief seaport of the Abd-elWahid.
It was the disunion of the Syrian amirs, and the division between the Abbasids and the Fatimites, that made possible the conquest of the Holy City and the foundation of the kingdom of Jerusalem.
The Latin power thus established and organized in the East had to face in the north a number of Mahommedan amirs, in the south the caliph of Egypt.
The atabegs formed a number of dynasties, which displaced the descendants of the Seljukian amirs in their various principalities.