Abu Yusuf Yaqub al-Mansur was the third Almohad caliph and the principal builder of the dynasty's architectural and intellectual culture. He was born in Marrakesh in 1160, the son of Yusuf I and grandson of Abd al-Mu'min, and succeeded his father in 1184 at the age of twenty-four after Yusuf's death from wounds suffered at the siege of Santarém.
His reign of fifteen years was the high point of Almohad political and cultural achievement. The decisive victory at the Battle of Alarcos in 1195, in which al-Mansur defeated a Castilian army under Alfonso VIII and pushed the frontier of al-Andalus back to its Almoravid-era limits, gave him the regnal name al-Mansur ("the victorious") on the model of the Abbasid caliph of the same epithet. The Andalusi-Maghrebi sphere remained politically unified for the duration of his reign.
Al-Mansur's architectural patronage produced the principal late twelfth-century Almohad monuments. The Koutoubia minaret of Marrakesh in its present form, the Hassan Tower of Rabat, and the Giralda of Seville were all initiated under his direction in the 1180s and 1190s; together they constitute the principal monumental record of Almohad imperial culture and the architectural template for subsequent Marinid and Saadian construction.
His patronage extended to the Andalusi-Maghrebi philosophical synthesis associated with Ibn Tufayl and Ibn Rushd, both of whom served at his court. Ibn Rushd's commentaries on Aristotle were largely composed under al-Mansur's patronage, although a late-reign turn against the philosophical tradition led to Ibn Rushd's brief exile to Lucena in 1197. Al-Mansur died at Marrakesh in 1199 and was succeeded by his son Muhammad al-Nasir, whose defeat at Las Navas de Tolosa in 1212 began the long Almohad collapse.