If you want to give your baby a traditional Irish name, forget about Siobhan, Sinead, and Sean. Instead, consider Conor, Cormac, or Niall.
Parents who choose “traditional” Irish names for their children in order to be patriotic will have to think again. A new study has found that many names thought to be from auld Ireland, including Sean, arrived with the Anglo-Normans in the 12th century.
Other names introduced by the Anglo-Normans include Eilis, Liam, Seamus, Ralph, Richard and Muiris, all of which only began appearing in Irish records after the invaders turned up. [Link]