have reached the age of 100. The Almoravid power was at its height at Yusuf's death: the Moorish empire then included all of Northwest Africa as far eastward as Algiers, and all of Iberia south of the Tagus and as far eastward as the mouth of the Ebro, and including the Balearic Islands. In 1108 Tamim Al Yusuf defeated the Kingdom of Castile at the Battle of Uclés. Yusuf did not reconquer much territory from the Christian kingdoms, except that of Valencia; but he did hinder the progress of the Christian Reconquista by uniting al-Andalus. In 1134, at the Battle of Fraga, the Almoravids were victorious and even succeeded in slaying Alfonso the Battler in the battle. Decline Under Yusuf's son and successor, Ali ibn Yusuf, Sintra and Santarém were added, and he invaded Iberia again in 1119 and 1121, but the tide had turned, as the French had assisted the Aragonese to recover Zaragoza. In 1138, Ali ibn Yusuf was defeated by Alfonso VII of León and Castile, and in the Battle of Ourique (1139), by Afonso I of Portugal, who thereby won his crown. Lisbon was conquered by the Portuguese in 1147. According to some scholars, Ali ibn Yusuf represented a new generation of leadership that had forgotten the desert life for the comforts of the city. He was defeated by the combined action of his Christian foes in Iberia and the agitation of the Almohads (Muwahhids) in Morocco. After Ali ibn Yusuf's death in 1143, his son Tashfin ibn Ali lost ground rapidly before the Almohads. In 1146 he was killed in a fall from a precipice while attempting to escape after a defeat near Oran. His two successors were Ibrahim ibn Tashfin and Ishaq ibn Ali, but their reigns were short. The conquest of the city of Marrakesh by the Almohads in 1147 marked the fall of the dynasty, though fragments of the Almoravids continued to struggle throughout the empire. Among these fragments, there was the rebel Yahya Al-Sahrāwiyya, who resisted Almohad rule in the Maghreb for eight years after the fall of Marrakesh before surrendering in 1155. Also in 1155, the remaining Almoravids were forced to retreat to the Balearic Islands and later Ifriqiya under the leadership of the Banu Ghaniya, who were eventually influential in the downfall of their conquerors, the Almohads, in the Eastern part of the Maghreb. Culture Religion The Almoravid movement