William de Montgomerie "de Talvas," was Count of Ponthieu, Montgomerie,Belesme and Alencon, who placed himself at the head of the affairs of hishouse during his father's imprisonment in England. Uniting in himself hisfather's large possessions, with those of his mother's wealthy family, hewas one of the wealthiest vassals of the crown. William did not get hisinheritance without a struggle, for during his father's captivity theKing of France had ceded the County of Alencon to Thibault, Count ofBlois, who in turn had given it to his brother Stephen, Count of Mortain.The latter's tyrannical conduct aroused the Alencais against him andthey, with Arnulphy, William's uncle, with help of Fulke, Count of Anjou,finally conquered the city and castle and the Count of Anjou, by histreaty with Henry I, remitted it to the King in order that he shouldinvest William with it, which was done in 1119. In 1146 William took upthe cross for the Holy Land with his son Guy, one authority saying hefitted out an army for Palestine at his own expense. He died June 20,1172. His wife was Helen or Alice, daughter of Eudes, Count of Burgandy,by whom he had Guy, John, Adela or Hele or Ala, called de Talvas, whomarried William de Warren, Earl of Warren and 3rd Earl of Surrey. Theironly daughter and heiress, Isabel de Warren, married HamelinePlantagenet, natural brother of King Henry II.