The Battle of Sagrajas (23 October 1086), also called Zalaca or Zallaqa (Arabic: معركة الزلاقة, romanized: Maʿrakat az-Zallāqa), was a battle between the Almoravid army led by their King Yusuf ibn Tashfin and an army led by the Castilian King Alfonso VI. The battleground was later called az-Zallaqah (in English "slippery ground") because of the poor footing caused by the tremendous amount of blood shed that day, which gave rise to its name in Arabic.