The growth of servitude in an expansive economic and legal climate is a thirteenth-century pattern not unique to Catalonia, but that principality shows particularly clearly the elaboration of ideas of liberty versus servitude. For the Iberian Peninsula, historians' attention to social differentiation has been focused on conflicts among religious communities under Christian rule, especially the degree of autonomy or subjugation experienced by Jews and Muslims in the wake of the conquests of Andalucia by Castile and of Valencia by Aragon-Catalonia. Less work has been done on the definitions of free and unfree status developed behind the frontier and within the Christian population in Catalonia itself, and more particularly in Old Catalonia, that is, the territories which by the thirteenth century were defined as lands north and east of the Llobregat River (essentially the area of the Carolingian Spanish Mark).

In certain respects this article revisits a topic I considered twenty years ago: the expansion of serfdom in a prosperous era and in relation to more – rather than less – law, order, and centralized government. As opposed to the rise of the seigneurie banale, conventionally situated in the years around 1000, this change in the condition of the peasantry was the result of increasing administrative structure and the growth of state institutions rather than a symptom of untrammeled seigneurial violence. Or, insofar as it did involve seigneurial violence, the oppression of the peasants was sanctioned, not merely tolerated, by the ruler, the king of Aragon-Catalonia.