In 1195, Alfonso VIII of Castile was defeated by the Almohads in the Battle of Alarcos. After this victory the Almohads took several important cities: Trujillo, Plasencia, Talavera, Cuenca, and Uclés. Then, in 1211, Muhammad al-Nasir crossed the Strait of Gibraltar with a powerful army, invaded Christian territory, and captured Salvatierra Castle, the stronghold of the knights of the Order of Calatrava. The threat to the Hispanic Christian kingdoms was so great that Pope Innocent III called Christian knights to a crusade.
The Battle of Las Navas de Tolosa was an important turning point in the Reconquista and in the medieval history of Spain. The Christian forces of King Alfonso VIII of Castile were joined by the armies of his rivals, Sancho VII of Navarre and Peter II of Aragon, in battle against the Almohad Muslim rulers of the southern half of the Iberian Peninsula. The caliph al-Nasir (Miramamolín in the Spanish chronicles) led the Almohad army, made up of people from all over the Almohad Caliphate.
The crushing defeat of the Almohads significantly hastened their decline both in the Iberian Peninsula and in the Maghreb a decade later. That gave further impulse to the Christian Reconquest and sharply reduced the already declining power of the Moors in Iberia. Shortly after the battle, the Castilians took Baeza and then Úbeda, major fortified cities near the battlefield and gateways to invade Andalusia.