Catholicism is not and never was a religion. At various points in its history, the Roman Catholic Church (as opposed to the short-lived Catholic Church) always has been either a form of government/empire, a political movement, or an occupying power (or all three). The religious overtones are just by-the-by. That’s not to say other religions didn’t try to copy their success, but nobody ever came close to the Catholics for depth and breadth of social control. The key innovation IMO was ensuring that subjects, sorry, the faithful, swear allegiance to the Church rather than to God (religion) or to a ruler/country (common-or-garden nationalism). Still massively successful, although the reign-of-terror business model has fortunately had its day.