Private property in land has no justification except historically through power of the sword. In the beginning of feudal times, certain men had enough military strength to be able to force those whom they disliked not to live in a certain area. Those whom they chose to leave on the land became their serfs, and were forced to work for them in return for the gracious per mission to stay. In order to establish law in place of private force, it was necessary, in the main, to leave undisturbed the rights which had been acquired by the sword.