Battle of Cervera
[5] Almanzor crossed the Duero and invaded Castile near Madinat Selim, where he sighted an army under Sancho García and the "Galician kings",[6] consisting of troops from as far as Pamplona and Astorga.
[7] Almanzor passed by the fortresses of Osma, San Esteban de Gormaz, and Clunia, which had been in Muslim hands for several years at that point.
Sancho, who had been elected leader of the entire army by the assembled troops, was encamped at the rock of Yarbayra (Peña de Cervera), a central location, well situated for supplies, and inaccessible due to its geography.
Almanzor was aware of his disadvantaged position—the Christians had a stronger camp and better sightlines, with a large open field before them—but his viziers could not agree on how to proceed.
Then, without planning and without strategy, the Christian host descended on the unsuspecting Muslims and the battle soon evolved into a general mêlée.
Almanzor's right and left columns were attacked simultaneously and soon fell back, which inspired the Christians to press their advantage even more boldly.
According to the eyewitness Jalaf ibn Husayn, Almanzor, with his escort, observed the action from atop a short hill near the field.
Ibn al-Khatib notes that the most outstanding fighter on the Muslim side was Abd al-Malik, Almanzor's son, stressing that this was "by unanimous opinion" without any favoritism and that he excelled even the famous Berber cavalry.
Gonzalo Martínez Díez speculates that if the Christians had not met Almanzor at Cervera, the hajib would have gone on to devastate Burgos as he had already Barcelona, Pamplona, León, and Santiago de Compostela.
His poem 105 is a bitter recollection of the campaign, including a reference to the brief invasion of Pamplona and the burning of the monastery of Santa Cruz de la Serós.
"[18] What the Christian annals have in common that the Arabic sources do not share is the stressing of the leadership of García Gómez of the Banu Gumis clan, one of whose comital members is recorded as killed in battle and beheaded by Ibn al-Khatib.
