The July 16 1212 battle of Las Navas de Tolosa is considered a major turning point in the history of Medieval Iberia. The forces of King Alfonso VIII of Castile were joined by the armies of his Christian rivals, Sancho VII of Navarre, Peter II of Aragon and Alfonso II of Portugal in battle against the Muslim Almohad rulers of the southern half of the Iberian Peninsula. Caliph al-Nasir led the Almohad army.
The Pope called European knights to a crusade.
The defeat of the Almohads significantly hastened their decline both in the Iberian Peninsula and in the Maghreb: a decade later, this would give further momentum to the Christian Reconquest begun by the kingdoms of northern Iberia centuries before, resulting in a sharp reduction in the already declining power of the Moors in the Iberian Peninsula.
Thirty-six years later, Granada was the sole city in the Iberian peninsula still in Muslim hands, and the kingdom of Granada was a vassal state of Castile.