I’ve been meaning to write about this topic for the longest time, ever since a reader asked me, ‘Can you assume Catholic or Protestant for a family on the basis of their children’s first names?’
And my shorter answer is: No. No, you cannot infer a religious affiliation for your Irish ancestors on the basis of their children’s first names (or forenames). The only way to confidently ascertain your ancestor’s religion is to find evidence of religious affiliation in a reliable source (in a parish register, for example, or in a cemetery record).
And my longer answer (No, not necessarily, but…) is forthcoming…
But in the meantime, I was reminded of this question when I looked at the top ten first names in my genealogy database. The majority of individuals in this database were of Irish Catholic origin (but the database includes a significant minority of French Canadians, who were also Catholic). And here are the top ten first names:
Of the above list of names, I would say that Patrick, Michael, and Bridget warrant a presumption in favour of Irish Catholic. Whereas Mary, John, James, Margaret? maybe Irish, maybe English, maybe Scottish, who knows? Catholic, Anglican, or Presbyterian: again, who knows? The only way to confidently ascertain is to get serious with the records.
Don’t expect every Irish Catholic ancestor in your family tree to announce himself the product of a Catholic Gaeltacht with a name like Séamus O’Shaughnessy. Some of your Irish RC ancestors may have had names like John Smith.
By the way, there is no Séamus O’Shaughnessy in my database; I just pulled that name out of a hat. There are certainly some Irish Catholic Smiths in my database, though.