In 1131, at the age of eleven, he was anointed as his father's successor; and when his father died in 1137 he became sole ruler of France. In the same year he married Eleanore de Poitou, Duchess of Aquitaine, so extending the Capetingian lands to the Pyrenees. He continued his father's program of appointing trustworthy people of lower origin to the administration of his government, thus improving the prestige of the monarchy. From 1141 to 1143 he was involved in a fruitless conflict with Thibaut, Count of Champagne, and the papacy. After this period his relations with the popes improved to such an extent that he supported Pope Alexander II against Frederick Barbarossa and even allowed the pope refuge in France. However, the main threats to his kingdom came from Geoffrey, Count of Anjou, and later from Geoffrey's son, the future Henry II, King of England. When Louis VII went on crusade, he took his wife with him. However, on their return he divorced her, the grounds officially being consanguinity, but the reasons were her rumoured affairs. Almost immediately she married King Henry II of England, taking Aquitaine with her. Louis VII then married Constance of Castile and, when she died, he married Alix de Champagne who became the mother of his son and heir, the future King Philippe II August. Louis VII might have defeated King Henry II had he made a concerted attack instead of the half-hearted attacks on Normandy, while at the same time France was spared attacks from the Anglo-Normans because of their internal quarrels. He also benefited from the long-standing quarrel between Henry II and Thomas Becket, Archbishop of Canterbury, and a revolt of Henry's sons. 
 

Source: Leo van de Pas