When Geoffrey Martel died without direct heirs he left Anjou to his nephew Geoffrey III of Anjou, Fulk le Réchin's older brother. Fulk fought with his brother, whose rule was deemed incompetent, and captured him in 1067.Under pressure from the Church he released Geoffrey. The two brothers soon fell to fighting again, and the next year Geoffrey was again imprisoned by Fulk, this time for good. Substantial territory was lost to Angevin control due to the difficulties resulting from Geoffrey's poor rule and the subsequent civil war. Saintonge was lost, and Fulk had to give the Gâtinais to Philip I of France to placate the king. Much of Fulk's rule was devoted to regaining control over the Angevin baronage, and to a complex struggle with Normandy for influence in Maine and Brittany (wikipedia)
Nobility, youngest of the two sons of Geoffrey II Ferreol, Count de Gatinais and Chateau-Landon and Ermengarde de Anjou. After several years of fighting with his brother Geoffrey over the power in Samur he was able to imprison him in 1067. Under the pressure of the church he had to release him and the fighting started anew. In the following year he was able to imprison him permanently and he succeeded him in Anjou and Tours. During Geoffreys reign and their fighting large parts of their territories were lost. Guillaume VIII de Aquitaine for example was able to conquer the Saintonge and Philipp I received the Gatinais to appease him. Even after his brothers imprisonment he had to fight agianst his barons who tried to revolt several times. Even his eldest son was no exception, Geoffrey III conquered Angers in 1103 and forced Fulk to share his power. Fulk was married five times; his first wife Hildegarde de Beaugency bore him a daughter but died after two years of marriage. Secondly he married Ermengarde de Bourbon who bore him his son Geoffrey but divorced her in 1176. His third and fourth marriage were dissolved soon after the wedding for consanguinity. In 1089 he married Bertrade de Montfort who bore him his second son, Fulk, and who left him to become the wife of Philipp I (findagrave.com)