Fulk was originally an opponent of King Henry I of England and a supporter of King Louis VI of France, but in 1118 or 1119 he allied with Henry when he arranged for his daughter Matilda to marry Henry's son William Adelin. Fulk went on crusade in 1119 or 1120, and became attached to the Knights Templar (Orderic Vitalis). He returned, late in 1121, after which he began to subsidize the Templars, maintaining two knights in the Holy Land for a year. Much later, Henry arranged for his own daughter Matilda to marry Fulk's son Geoffrey, which she did in 1127 or 1128.