Ideological arguments are commonly sustained by an appeal to the past, an appeal either to see precedents in history for new claims being advanced, or to see history itself as a development towards the point of view being advocated or denounced. Perhaps the most influential example from British history of this prescriptive use of historical information is provided by the ideological arguments associated with the constitutional revolution of the seventeenth century. It was from a propagandist version of early English history that the ‘whig’ ideology associated with the Parliamentarians – the ideology of customary law, regulated monarchy and immemorial parliamentary right – drew its main evidence and strength. The process by which this ‘whig’ interpretation of history was bequeathed to the eighteenth century has already been traced. But it remains to analyse the various ways in which an awareness of the past became a politically relevant factor in the upheavals of the previous century. The acceptance of the whig view of early English history represented the triumph of one among several conflicting ideologies that had relied on the same historical support. And despite the resolution of the conflict by the widespread acceptance of the whig view, the whigs themselves were covertly influenced by the rival ideologies which their triumph might seem to have suppressed. It is the further investigation of these historical and political commitments that will be attempted here.