If you are working on your family history, be careful of what you are told. What you are told could be made up or it could be misinterpreted. Document everything and then crosscheck it with other documents.
The most blatant tale that I can think of is what my mother told me around a St. Patrick's Day. She said, "We are Orange Irish." One, her ancestors were from England and Germany, not Ireland. Two, she didn't know any of her in-laws besides her U.S. born father-in-law and German-born mother-in-law.
So far, I have found only one Magree ancestor going back four generations that was not born in the United States. My great grandfather, John James Richard Magree, was born in Liverpool, England of an American father and an English mother. Given that her maiden name was Pope, she may or may not have had Irish ancestors. Many Irish immigrated to Liverpool. However, all of the other records that I have for him say he was born in the U.S. and more specifically in Brooklyn.
I do know that the name Magree is centered in Kilkenny, Ireland and some of those Magrees are buried in a Catholic Church cemetery. If my Magree ancestors were from there, they most likely would have been Catholic.
I was told that my grandfather was born in Poughkeepsie, New York. But his death certificate gives Brooklyn, his parents were in a Brooklyn city directory at the time of his birth, and one of his sister's birth certificates gives that same address. But somebody else on ancestry.com has that sister born in Poughkeepsie!
I read the death certificate of my paternal grandmother's father as his birthplace being "Schlossing"; the information was provided by one of his sons. Knowing my grandmother was born in Germany I kept looking for a town with that name. Then it dawned on me that it should be "Schlesien", German for Silesia. Silesia is now mostly in Poland. Somebody else on ancestry.com had his birth as "Schlassing". As part of checking if my grandmother may have been Catholic, I looked up Silesia. I learned that there is a Silesian German and the speakers call themselves Schlässinger. I have since found out that my grandmother's town of leaving was called Osseg; it is now Osiek in Polish.
I have learned so much family history in the last thirty years, but I will need another thirty years to even fill in details about the people whose names I know.
But, regardless of where my ancestors came from, I do not consider myself Orange Irish or Green Irish or German or Polish or even Brooklynite:) My nationality is American!
See also What nationality are you? An irrelevant question!