How did the crusades affect the feudal systems?

The crusades could not fail to affect in many ways the life of western Europe. For instance, they helped to undermine feudalism. Thousands of barons and knights mortgaged or sold their lands in order to raise money for a crusading expedition. Thousands more perished in Syria and their estates, through failure of heirs, reverted to the crown. Moreover, private warfare, that curse of the Middle Ages, [20] also tended to die out with the departure for the Holy Land of so many turbulent feudal lords. Their decline in both numbers and influence, and the corresponding growth of the royal authority, may best be traced in the changes that came about in France, the original home of the crusading movement.It also influnced the fuedal system because the nobels sold land and bought land.