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
Mac Maoláin presence of a collateral family in the province of Leinster. MacMullan and McMullen families are recorded in the Barony of Uíbh Echach (Clanna-Rory Irish Genealogical Foundation page 16), as Bishops of the Diocese of Connor and Down with the Bishops seat (the seat of MacMullen) identified as the townland of Cabra, parish of Clonduff, ancient territory of Mac Aenghusa (Magennis), Lords of Iveagh. Mac Maoláin Mac Maoláin Gaelic-Irish surname. Mac Maoláin was a surname borne by a number of unrelated families in Gaelic Ireland, anciently found in Breifne, Mide, Brega, Connacht and Ulster. Now anglicized MacMullan, MacMullen, MacMoylan, McMullen, McMullan,