When the Zirids renounced Shia Islam and recognized the Abbasid Caliphate in 1048, the Fatimids sent the Arab tribes of the Banu Hilal and the Banu Sulaym to Ifriqiya. The Zirids attempted to stop their advance towards Ifriqiya, they sent 30,000 Sanhaja cavalry to meet the 3,000 Arab cavalry of Banu Hilal in the Battle of Haydaran of 14 April 1052. Nevertheless, the Zirids were decisively defeated and were forced to retreat, opening the road to Kairouan for the Hilalian Arab cavalry. The Zirids were defeated, and the land laid waste by the Bedouin conquerors. The resulting anarchy devastated the previously flourishing agriculture, and the coastal towns assumed a new importance as conduits for maritime trade and bases for piracy against Christian shipping, as well as being the last holdout of the Zirids.