Historians are generally agreed that Lancashire was the most Catholic and the most Jacobite county in England at the time of the 1715 rebellion. Indeed, final confirmation of this connection would seem to have been established by Professor Paul Kléber Monod. In his book, Jacobitism and the English People 1688–1788, Monod has stated that ‘Lancashire had the largest [Catholic] recusant population in England’ at the end of the seventeenth century, and that of the 688 listed English Jacobite rebels captured at Preston in 1715, 366 were from Lancashire, 227 from Northumberland, 78 from other counties, six from Ireland and eleven from unidentified places. Monod also discovered the religious affiliations of four-fifths of the Lancashire rebels and noted that 76 per cent of them were Roman Catholics. With these vital statistics in our possession it would seem that there is no need for further research on Lancashire Catholicism and Jacobitism in the early eighteenth century. But certain questions, ignored or barely touched on by Monod and other historians, need answering. First, how many Catholics were there in Lancashire in about 1715, what was their geographical distribution and social composition, and how far were they dominated by the gentry? Secondly, what was the social composition of the various Lancashire Catholic groups: the active Jacobites, the passive Jacobites and those of unknown allegiance? Thirdly, how do the Catholic and Protestant Jacobite rebels of Lancashire compare from a social and political standpoint? Finally, and confining ourselves mainly to the Catholic gentry, how strong a link was there in Lancashire between the Royalism of the Civil Wars (1642–48) and the Jacobitism of the 1715 rebellion?