The abstract of this article begins "Historians are generally agreed that Lancashire was the most Catholic and the most Jacobite county in England at the time of the 1715 rebellion".
The Wikipedia article on "Recusancy" says "Recusancy was historically focused in Northern England, particularly Cumberland, Lancashire, Yorkshire and Westmoreland".
And the Wikipedia article on "Catholicism in England" says "In North West England one in five are Catholic, a result of large-scale Irish migration in the nineteenth century as well as the high number of English recusants in Lancashire".
My question is why was Lancashire and the North West of England home to so many recusants/Catholics?