Battle of Sagrajas The Battle of Sagrajas ( 23 October 1086 ) , also called Zalaca or Zallaqa , ) , was a battle between the Almoravid army led by general Yusuf ibn Tashfin and a Christian army led by the Castilian King Alfonso VI . The battleground was later called " az - Zallaqah " ( in English " slippery ground " ) because the warriors were slipping all over the ground due to the tremendous amount of blood shed that day , and this gives rise to its name in Arabic . Preparations . After Alfonso VI , King of León and Castile captured Toledo in 1085 and invaded the taifa of Zaragoza , the emirs of the smaller taifa kingdoms of Islamic Iberia found that they could not resist against him without external assistance . In 1086 Yusuf ibn Tashfin was invited by them to fight against Alfonso VI . In that year , he replied to the call of three Andalusian leaders ( Al - Mu ' tamid ibn Abbad and others ) and crossed the straits to Algeciras and moved to Seville . From there , accompanied by the emirs of Seville , Granada and Taifa of Málaga marched to Badajoz . Alfonso VI abandoned the siege of Zaragoza , recalled his troops from Valencia and appealed to Sancho I of Aragon for help . Finally he set out to meet the enemy northeast of Badajoz . The two armies met each other on 23 October 1086 . Alfonso VI of Castile reached the battleground with some 2 , 500 men , including 1 , 500 cavalry , in which 750 were knights , but found himself outnumbered . The two leaders exchanged messages before the battle . Yusuf ibn Tashfin is reputed to have offered three choices to the Castilians : convert to Islam , to pay tribute ( jizya h ) , or battle . Battle . The battle started on Friday at dawn with an attack from Castile . Yusuf ibn Tashfin divided his army into 3 division s . The first division was led by Abbad III al - Mu ' tamid , the second division was led by Yusuf ibn Tashfin and the third division consisted of black African warriors with Indian sword s and long javelin s . Abbad III al - Mu ' tamid and his division battled with Alfonso VI alone till the afternoon , then Yusuf ibn Tashfin and his division joined the battle and circled Alfonso VI and his troops . Alfonso ' s troops panicked and started to lose ground , then Yusuf ordered the third division of his army to attack and finish the battle . Aftermath . At least half the Castilian army was lost . One lone source claims that only 500 knights returned to Castile , although others do not support this low figure , so it seems that most of the nobility survived . The dead included counts Rodrigo Muñoz and Vela Oveguez . King Alfonso VI sustained an injury to one leg that caused him to limp for the rest of his life . Casualties were also heavy on the Almoravid side , specially for the hosts led by Dawud ibn Aysa , whose camp was even sacked in the first hours of battle , and by the emir of Badajoz , al - Mutawakkil ibn al - Aftas . The Sevillan emir al - Mu ' tamid had been wounded in the first clash but his personal example of valour rallied the al - Andalus forces in the difficult moments of the initial Castilian charge led by Alvar Fañez . Those killed included a very popular imam from Cordoba , Abu - l - Abbas Ahmad ibn Rumayla . The battle was a decisive victory for the Almoravids but their losses meant that it was not possible to follow it up although Yusuf had to return prematurely to Africa due to the death of his heir . Castile suffered almost no loss of territory and was able to retain the psychologically important city of Toledo , occupied the previous year . However , the Christian advance was halted for several generations while both sides regrouped .