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 Aodhagáin Flann Mac Aodhagáin up to the year 1643. The surname has been Anglicised in a variety of ways, including as Mac Egan, Egan, Eagan, Keegan, or Keigan, McKiegan, and McKagan. Muirchertach Mac Aodhagáin Muirchertach Mac Aodhagáin Muirchertach Mac Aodhagáin Muirchertach Mac Aodhagáin Muirchertach Mac Aodhagáin Muirchertach Mac Aodhagáin Muirchertach Mac Aodhagáin Mac Aodhagáin Mac Aodhagáin (English: Egan or Keegan), is an Irish Gaelic clan of Brehons who were hereditary lawyers - firstly to the Ó Conchobhair Kings of Connacht, and later to the Burkes of Clanricarde. The earliest surviving Irish law manuscript, "In Senchas Már", was written prior to 1350