Ó Díomasaigh

Rev Patrick Woulfe

Ó DÍOMASAIGH—IO Dymasa, O Demsy, O'Dempsey, Dempsey; 'descendant of Díomasach' (proud). The O'Dempseys, who are of the same stock as the O'Connors of Offaly, derive their descent from Ros Failghe, eldest son of Cathaoir Mor, King of Ireland in the second century, and were long one of the most powerful families in Leinster. Their territory was Clann Mhaoilughra, an extensive district on both sides of the river Barrow, and comprising the baronies of Portnahinch in Leix, and Upper Philipstown, in Offaly. During the reign of Elizabeth, the O'Dempseys were on friendly terms with the English, and their estates for a time escaped confiscation; Terence O'Dempsey was knighted by Essex in 1599, and in 1631 created Baron of Philipstown and Viscount Clanmalier. They took, however, an honourable part in the Confederation of Kilkenny, and later on were staunch adherents to the cause of James II. For their loyalty on this occasion they suffered the loss of their estates.

Alphabetical Index to Irish Surnames