Costello
Mac Oisdealbhaigh · son of Oisdealbhach
Costello is Mac Oisdealbhaigh in Irish, said mak USH-dal-vee, and means son of Oisdealbhach.
The first Norman family to take a Mac name instead of a Fitz: Mac Oisdealbhaigh, son of Jocelyn de Angulo. Gaelicisation in one generation, written into the surname.
How it changes
- A man: Mac Oisdealbhaigh
- His daughter: Nic Oisdealbhaigh
- A woman who married into it: Bean Mhic Oisdealbhaigh
- The family together: Mhic Oisdealbhaigh
Where it comes from
Mayo
Also spelt
Costello, Costelloe, Costigan
A name, not a pedigree
This is where the name came from, which is not the same as where you came from. Names were translated, anglicised, taken on by tenants and neighbours, and carried in by settlers who were no relation to the family that started them. To follow your own line, the 1901 and 1911 censuses are free and searchable, and give the county each person was born in.