Jews, Christian Society, and Royal Power in Medieval Barcelona traces the development of the Jewish community of Barcelona from 1050 to 1300. Elka Klein challenges the common perception that medieval Jews lived in relative isolation from the surrounding society, argues for the existence of significant cultural common ground between Jews and Christians, and proposes a new model for understanding Jewish communal autonomy and the relationship between Jews and their rulers. Klein traces the development of the Jewish community of Barcelona in two contexts: the parallel development of the city of Barcelona and the changing relationship of the king to urban communities, Jewish and Christian. Until the later twelfth century, the Jewish community, like the Christian city of Barcelona, was left mostly to its own devices by the counts of Barcelona, who had neither the interest nor the power to interfere in internal affairs. Klein draws on both Hebrew and Latin sources to offer a picture of a communal elite whose power, mostly informal, derived from their influence within the community. This system changed in the later twelfth century as a result of the expansion of comitial-royal administration. Four Jewish families used their positions as bailiffs, accountants, and secretaries to consolidate power within their community. The rule of this courtier elite was short lived; two episodes of communal conflict in the early thirteenth century and increased royal activism led to the institution of a new regime of elected officials in 1241. The book concludes with an examination of the new elite and the implications of increased royal interference in internal affairs. A central argument of Jews, Christian Society, and Royal Power in Medieval Barcelona is that it is necessary to distinguish between autonomy by default, resulting from the indifference of the ruler, who leaves a community to govern itself; and autonomy by design, guaranteed by selective royal interference. Against the view that royal interference undercut Jewish autonomy, Klein argues that autonomy by default left the community with insufficient power to enforce its decisions; because Catalan kings generally interfered in support of existing structures, autonomy by design in fact strengthened the community. This book contributes to ongoing debates about the relationship between the cultures of the three religions in the Iberian peninsula. It joins a body of recent scholarship arguing that medieval European Jews and Christians shared considerable cultural common ground.