This paper seeks to rethink the historiography on the genesis of parliament in England and the Spanish kingdoms, and argues that, for a variety of methodological reasons, historians have failed to grasp the essential features that distinguished parliamentary assemblies from other medieval institutions. As a consequence, this paper negotiates interpretive difficulties, including anachronistic usage of historical context and chronology, by way of a comparative treatment that calls into question the extent to which the first parliaments were adversarial institutions. Accordingly, it problematizes the standard view that regards the emergence of parliament as among the first institutional challenges to the power of monarchical government. In discussing the methodological problems presented by the narratives on the origins of parliamentary assemblies, my forthcoming dissertation will propose an alternative paradigm, which sees the origins of parliament as an institutional transformation within an evolving feudal structure and conclude that, far from antagonizing and restricting the power of the monarchy, these assemblies served instead the growing needs of an increasingly centralized medieval state and were essentially, in their original form, a monarchical device.