However, once out of Charles's reach, Louis declared the treaty invalid, and set about building up his forces. His aim was to destroy Burgundy once and for all. Nothing was more odious to Louis' dream of a centralized monarchy than the existence of an over-mighty vassal such as the Duke of Burgundy. War broke out in 1472. Duke Charles laid siege to Beauvais and other towns. However, these sieges proved unsuccessful; the Siege of Beauvais was lifted on 22 July 1472, and Charles finally sued for peace. Philippe de Commines was then welcomed into the service of King Louis.