 For Marx, however, exploitation was a phenomenon that characterized all class-based societies, not only capitalism. Indeed, it is feudal society, not capitalism, where the exploitative nature of class relations is clearest. Under feudalism, it is readily apparent that serfs use some of their labor power for their own benefit, while another part (the corvée) is used for the benefit of the feudal lord. In contrast, under slavery workers appear to work entirely for the benefit of their masters (though in reality a part of their labor goes toward providing for their own subsistence). And under capitalism workers appear to work entirely for the benefit of themselves, selling their labor to capitalists as free independent contractors (Cohen 1978: 332–3).