I myself am 1/4th English, ancestrally, and my English family members today are Catholics, as there was about 100 years ago some Irish on that side, as well as obligatory Anglicanism. My Grandma's mum is 100% ethnic English (Anglican religion), and her dad was half Irish half Swedish, hence the Catholicism (my Swedish Great Great Grandfather converted from what we believe to be Lutheranism). Anyways, I've realized that Catholicism has had place in the British Empire for a long time, and when looking to the Irish this is one of the many reasons they once fought with the English over their island and rule. I'm aware the French Canadians had in treaty allowance of their Roman Catholicism, but was it so easily maintained?
When Ireland was under UK rule, was their Roman Catholicism purged, or was it allowed? What of the catholic French Canadians once they became subjects of the British Empire? What of Jacobian Scots, or the Spanish of Gibraltar? I'm very curious. I'm aware that nowadays it is no big deal at all your religion in the UK or Commonwealth, but I'm wondering how it used to be.
Catholics in Ireland certainly were oppressed. Big time. There is a famous phrase that stems from the famine days called "taking the soup" This was basically you had two choices: starve or convert to Church of England. This is called souperism. Basically if you decided not to starve it was called taking the soup.
Cite:Thomas Edward Jordan (1998). Ireland's Children: Quality of Life, Stress, and Child Development in the Famine Era
Then of course there's Oliver Cromwell. A man still cursed here in Ireland to this day. Cromwell started a bloody campaign against the Irish catholics and English royalists in 1649 and ended in 1653. Over 200,000 Irish are believed to have died during this time. All catholic land was confiscated during this time too in the "Act for the Settlement of Ireland of 1652"
Cite: "Rather the region was chosen out of exaggerated respect for the impermeability of the Shannon line".
During this time there was a famous phrase "Hell or Connaught" Which meant you can either die or be exiled to Connaught. Connaught is a province in the west of Ireland. It has awful farming conditions. So really you were going to die regardless.