The great officers who attended the court, commanded armies, or distributed justice must necessarily be paid and supported; but in what manner could they be paid?
In money they could not, because there was very little money then in Europe, and scarce any part of that little came into the prince's coffers.

The only method of paying them was by allotting lands for their subsistence whilst they remained in his service.

For this reason, in the original distribution, vast tracts of land were left in the hands of the king.

If any served the king in a military command, his land may be said to have been in some sort held by knight-service.

If the tenant was in an office about the king's person, this gave rise to sergeantry; the persons who cultivated his lands may be considered as holding by socage.