I have found this naming pattern very helpful and not just for the Irish. Old Irish Naming Patterns 1st son was named after the father's father. 2nd son was named after the mother's father. 3rd son was named after the father. 4th son was named after the father's eldest brother. 1st daughter was named after the mother's mother. 2nd daughter was named after the father's mother. 3rd daughter was named after the mother. 4th daughter was named after the mother's eldest sister.