The categorization of people by social stratum occurs most clearly in complex state-based, polycentric, or feudal societies, the latter being based upon socio-economic relations among classes of nobility and classes of peasants. Historically, whether or not hunter-gatherer, tribal, and band societies can be defined as socially stratified, or if social stratification otherwise began with agriculture and large-scale means of social exchange, remains a debated matter in the social sciences. Determining the structures of social stratification arises from inequalities of status among persons, therefore, the degree of social inequality determines a person's social stratum. Generally, the greater the social complexity of a society, the more social stratification exists, by way of social differentiation.