Yusef's cavalry was said to have included 6,000 shock troops from Senegal mounted on white Arabian horses. Camels were also put to use. On October 23, 1086, the Almoravid forces, accompanied by 10,000 Andalusian fighters from local Muslim provinces, decisively checked the Reconquista, significantly outnumbering and defeating the largest Christian army ever assembled up to that point. The death of Yusef's heir, however, prompted his speedy return to Africa. When Yusuf returned to al-Andalus in 1090, he saw the lax behavior of the taifa kings, both spiritually and militarily, as a breach of Islamic law and principles, and left Africa with the express purpose of usurping the power of all the Muslim principalities, under the auspices of the Abbasid caliph of Baghdad, with whom he had shared correspondence, and under the slogan "The spreading of righteousness, the correction of injustice and the abolition of unlawful taxes." The emirs in such cities as Seville, Badajoz, Almeria and Granada had grown accustomed to the extravagant ways of the west. On top of doling out tribute to the Christians and giving Andalusian Jews unprecedented freedoms and authority, they had levied burdensome taxes on the populace to maintain this lifestyle. After a series of fatwas and careful deliberation, Yusef saw the implementation of orthodoxy as long overdue. That year, he exiled the emirs 'Abdallah and his brother Tamim from Granada and Málaga, respectively, to Aghmāt, and a year later al-Mutamid of Seville suffered the same fate. When all was said and done, Yusef united all of the Muslim dominions of the Iberian Peninsula, with the exception of Zaragoza, to the Kingdom of Morocco, and situated his royal court at Marrakech. He took the title of Amir al-muslimin (Prince of the Muslims), seeing himself as humbly serving the caliph of Baghdad, but to all intents and purposes he was considered the caliph of the western Islamic empire. The military might of the Almoravids was at its peak. The Sanhaja confederation, which consisted of a hierarchy of Lamtuna, Musaffa and Djudalla Berbers, represented the military's top brass. Amongst them were Andalusian Christians and heretic Africans, taking up duties as diwan al-gund, Yusef's own personal bodyguard, including 2,000 black horsemen, whose tasks also included registering soldiers and making sure they were compensated financially. The occupying forces of the Almoravids were made up largely of horsemen, totaling no less than 20,000. Into the major cities of al-Andalus, Seville