"I'm Sorry, what?"
You never know what you'll find when you start a deep dive into an ancestor's history. Case in point is my father's biological family and the hunt for his father, in particular. So many peculiarities. The big one is this: my DNA tests show a connection to the Irish Catholic surname O'Donnell for many generations back. I have quite a few O'Donnells on my list of relatives.
However, I also know from DNA that I am related to living people who descend from a branch of MacDonalds from Scotland. And this is where it gets interesting. John MacDonald (b 1824) married Winnifred Welsh (b 1828) who beget their son, John (b 1861), who married Virginia Bolduc (b 1870). They had three children, one of whom is, I believe, my father's father, Frank MacDonald.
Still with me? Turns out that a John O'Donnell (b 1824) also married a Winnifred Welsh (b 1828). The dates and places all match up between John O'Donnell/MacDonald and Winnie. What's going on here? Well, somewhere around the 1870s, the O'Donnell became MacDonald.
And I can't for the life of me figure out why. All the children of John and Winnie were born O'Donnell but in later years, I find them as MacDonald. To further confound the mystery, I am DNA related to a Sarah O'Donnell/MacDonald. According to her birth (1851) and marriage (1871) certificates, Sarah was born O'Donnell. But on the birth certificates of each of her children, she is MacDonald. Also, I haven't yet been able to link this Sarah to my known O'Donnell ancestors.
Perhaps unsurprisingly, there is a John Peter O'Donnell (b 1898) from a different line, who married Josephine MacDonald (b 1902), formerly of my O'Donnell line. Are these two actually related? Cousins? I don't know as yet but I'm on the trail.