Enclosed land was under control of the farmer who was free to adopt better farming practices. There was widespread agreement in contemporary accounts that profit making opportunities were better with enclosed land.[9] Following enclosure, crop yields increased while at the same time labour productivity increased enough to create a surplus of labour. The increased labour supply is considered one of the causes of the Industrial Revolution.[10][page needed] Karl Marx argued in Capital that enclosure played a constitutive role in the revolutionary transformation of feudalism into capitalism, both by transforming land from a means of subsistence into a means to realize profit on commodity markets (primarily wool in the English case), and by creating the conditions for the modern labour market by unifying smallholders and pastoralists into the mass of agricultural wage-labourers, i.e. those whose opportunities to exit the market declined as the common lands were enclosed.[11]