The growth of military expenditures resulted in the seven-fold increase of Spanish clerical subsidies during the reign of Charles v (king of Spain, 1517–55). A source of collateral for Habsburg creditors, clerical contributions between 1519 and 1555 amounted to 3,666,000 ducats. The author makes sense of these numbers (about 7 per cent of Spanish royal revenue) by illustrating the strategies that the Castilian cathedral chapters used to limit their contributions toward the defence of the faith. The author's model is to transform the clerical defence mechanism into a ‘representative’ organism, although it remains unclear how the ‘assembly’ represented the Spanish Church. The author reveals that when such clerical assemblies convened they became sites of internal conflict characterised by local divisions and conflicts among the chapters. Over the course of fifty years, the Habsburgs and Rome were the players who subdued the chapters into providing annual contributions for the defence of the faith. While Rome conceded to the Habsburgs the legal right to collect clerical subsidies, the Spanish chapters appealed to Rome to pressure the crown to be less demanding and unobtrusive. The chapters struggled to achieve a platform of resistance and a consensus to reduce their liabilities. This book contributes to the literature on early modern ecclesiastical institutions, because it reveals how royal government extracted ecclesiastical wealth and how churchmen contested the implementation of military policies whenever such policies affected their incomes. The book is a detailed exposition of interaction between royal government and the cathedral chapters, and the author captures and represents a discourse of clerical resistance, exposing the sixteenth-century Castilian topos of the indigent vassal of the king, an impoverishment caused by royal service.