A defining feature of all early civilizations was the institutionalized appropriation by a small ruling group of most of the wealth produced by the lower classes. Economists commonly define wealth as the stock of goods and claims that individuals or corporate groups can give away or use to purchase goods and services. In modern industrial societies, where almost everything can be bought and sold, any sort of asset constitutes wealth (Polanyi 1944). In early civilizations, however, some types of goods did not circulate freely. Communal land, which could be inherited but not alienated, was clearly a source of wealth that economically advantaged its owners by comparison with groups that were landless. Agricultural workers who lacked their own land had to pay to use other people's, usually by surrendering a substantial portion of their production to its owners. Yet, while inalienable communal land constituted a source of wealth, it was not a form of wealth. In Peru the king gave gold objects to individuals as testimonials of his esteem for them or as rewards for service. Although these objects could be inherited, they could not be bought or sold. Thus, while they were valuable social assets, they too were not commodities, and hence did not constitute wealth. Palaces, temples, and tombs, which expressed the power of the upper classes, also fell into this category.