Passing through the province of Seville, the main Almohad army reached Cordova on June 30, reinforced by the few troops raised by the local governors and by a Christian cavalry contingent under Pedro Fernández de Castro, who held a personal feud against the Castilian king.

A cavalry detachment of the Order of Calatrava, plus some knights from nearby castles, tried to gather news about the Almohad strength and its heading; they were surrounded by Muslim scouts and almost massacred,[citation needed] but managed to provide information to the Castilian king.

Alfonso gathered his forces at Toledo and marched down to Alarcos (al-Arak, in Arabic), near the Guadiana River, a place which marked the Southern limit of his kingdom and where a fortress was under construction.

He intended on barring the access to the rich Tagus valley, and did not wait for the reinforcements the Kings Alfonso IX of León and Sancho VII of Navarre were sending.

The Castilian king put most of his heavy cavalry in a compact body, about 8,000 strong, and gave its command to Diego López de Haro, lord of Vizcaya.

The knights crashed against the Zanatas and Bani Marin and dispersed them; lured by the Amir's standard, they charged uphill: Vizier Abu Yahya was killed,[6] and the Hintata fell almost to a man trying to protect themselves.

The Arab right under Yarmun had been enveloping the Castilian flank and rear; at this point the best of the Almohad forces attacked, with the sultan himself clearly visible in the front ranks; and finally the knights were almost completely surrounded.

For the next two years, al-Mansur's forces devastated Extremadura, the Tagus valley, La Mancha and even the area around Toledo; they moved in turn against Montánchez, Trujillo, Plasencia, Talavera, Escalona and Maqueda.

But the caliph was losing interest in the affairs of the Iberian Peninsula; he was in poor health, his objective of retaining a hold over al-Andalus appeared to be a complete success, and in 1198 he returned to Africa.