This lecture takes its bearings from the observation that in early modern England generation was often understood as a unit of historical chronology. It examines the development of official and alternative histories of the Reformation before considering the processes by which contemporaries came to think of the Reformation as a past event rather than an unfinished and ongoing development. It explores the naming and dating of the Reformation and assesses how senses of religious change, upheaval and rupture contributed to creating enduring models of periodization, as well as to altering how sixteenth- and seventeenth-century society comprehended the passage of time. It will also engage with influential claims about the nature and transformation of both modes of historiography and regimes of temporality in this era.