The use and dropping of the "O" must be more than just the issue of getting a job or avoiding reprisals by non-Catholics. I have seen baptism registers at Catholic churches in Cork and Limerick in the mid-1800s that have the "O" for the family name in the baptism of one child and without the "O" for another child of the same family. I don't know why they would be inconsistent. I did hear that my grandfather wrote a poem about his cousin or uncle who stopped using the "O" in O'Regan. The poem was called "When Jimmy dropped the "O". I guess I could ask the same question about why some of the Fitzgeralds had a lower case "g" and others, including my ancestors had an upper case "G". Ray FitzGerald Researching O'Regan, Drake & FitzGerald in northeast Cork and Southeast Limerick.