The early second millennium was a pivotal moment in the history of Theravada Buddhism. Religious reforms carried out at Poonnaruva, then-capital of Sri Lanka, shaped the latter course of Buddhism across South and Southeast Asia. However, our understanding of these reforms has been over-determined by retrospective accounts written by male monastics, who focused on the heroic deeds of male monarchs. This book offers a radical revision of this narrative. Drawing on textual, inscriptional, numismatic, and material evidence from within the period itself, it reveals how the intellectual and social histories of Buddhism, politics, and gender were inextricably intertwined in Poonnaruva. In particular, it argues that debates over what it meant to be a "good Buddhist king" were intrinsically debates about Buddhist masculinity and about the proper relationship of gender to power.