It seemed equitable, that one who had cultivated and sowed a field, should reap the harvest: hence fiefs, which were at first entirely precarious were soon made annual.

A man who had employed his money in building, planting, or other improvements, expected to reap the fruits of his labor or expense: hence they were next granted during a term of years.

It would be thought hard to expel a man from his possessions who had always done his duty, and performed the conditions on which he originally received them: hence the chieftains, in a subsequent period, thought themselves entitled to demand the enjoyment of their feudal lands during life.

It was found, that a man would more willingly expose himself in battle, if assured that his family should inherit his possessions, and should not be left by his death in want and poverty; hence fiefs were made hereditary in families, and descended, during one age to the son, then to the grandson, next to the brothers, and afterwards to more distant relations.[*] The idea of property stole in gradually upon that of military pay; and each century made some sensible addition to the stability of fiefs and tenures.
[* Lib.Feud.lib.i.tit.

i.] In all these successive acquisitions, the chief was supported by his vassals; who, having originally a strong connection with him, augmented by the constant intercourse of good offices, and by the friendship arising from vicinity and dependence, were inclined to follow their leader against all his enemies, and voluntarily, in his private quarrels, paid him the same obedience to which, by their tenure, they were bound in foreign wars.