Costello (surname) to a Gaelic translation of Jocelyn, Jocelyn d'Angulo's given name. In fact, MacOisdealbhaigh is the Gaelic translation of his brother Hostilo (or Hostilio) d'Angulo's first name. Oisdealbh is a much more obvious translation of Hostilo. It is Hostilo's descendants who would bear the surname Mac Oisdealbhaigh (son of Oisdealbh or Hostilo). The surname would later be anglicized to Costello, Costelloe, and Costellow. Gilbert d'Angulo is also sometimes listed as the son of Jocelyn d'Angulo in error. Gilbert d'Angulo is the father of both Jocelyn and Hostilo. It occasionally has been adopted as a pseudonym or stage name by famous people
Forrestal (surname) Forrestal (surname) Forrestal or Forristal (Irish: Ó Fuireastal), is an old Irish surname common in the southeast of Ireland, namely in the counties of Kilkenny, Wexford and Waterford. The name has been spelled in many different forms, all of which are related to the same family including; O'Forristal, Forrestal, Forristal, Forestal, Forestal, Forrestall, Foristal, and in medieval times, Forstall. Forestell is a variation found in Canada. Also, in Gaelic Irish as Ó Fuireastal (pronounced O'Furristhawl), Mac Fuireastal, and Mac An Choill. The Forristals were rooted in Glenmore parish, County Kilkenny, where they held several castles, some of which were located