Page "Manorialism" Paragraph 23

Although not free, villeins were by no means in the same position as slaves: they enjoyed legal rights, subject to local custom, and had recourse to the law subject to court charges, which were an additional source of manorial income.

Sub-letting of villein holdings was common, and labour on the demesne might be commuted into an additional money payment, as happened increasingly from the 13th century.