The development of systematic social thought is inseparable from the changes in social organisation consequent upon the genesis, growth and periodic disruption of commodity production. With the emergence of an enduring international economy during the Iron Age came the universalistic ethical creeds of Lao-tse, the Buddha and the Hebrew prophets. Medieval feudalism was intellectually dominated by doctrines as hierarchical and predictable as the social relations which they justified. While ascendant capitalism, to take a number of polar cases, saw Adam Smith and Marx, J. S. Mill and Machiavelli, Weber and Lenin. The historical growth of the productive forces has, in an irregular and anything but linear fashion, transformed the social relations of mankind, and it is in relation to the principal points of transformation that the major developments in social theory have mainly taken place.