De Gascún
de GASCÚN—XI—de Gascoyn, Gascoigne, Gaskin; Norman 'de Gascoyne,' i.e., of Gascony, French Gascogne, an old province in the S.W. of France; the name of an old Norman family in Dublin. The form 'Gascoigne' represents a later immigration.
Alphabetical Index to Irish Surnames