From Michael Corleone to Tony Soprano, on-screen mobsters are far more violent than virtuous. Yet despite dealings in organised crime — and their ability to justify murder as "business" — these men, and their families, identify as Catholics. Baptisms, confessions and other religious sacraments are strewn throughout The Godfather trilogy and the HBO series The Sopranos.

You might think that religion — like pasta or Italian curse words — is just another tool that screenwriters use to emphasise the mobsters' migrant backgrounds. But there's more to it than that. As one film critic argues, Catholicism was inserted into this violence-laden genre to get movies past American censors in the early 20th century.