Dempsey


Dempsey is a surname of Irish origin.

Background

Dempsey is an anglicised form of Ó Díomasaigh, 'descendant of Díomasach'; this personal name is the Irish adjective díomasach 'proud'. The family originated in the Kingdom of Uí Failghe.
According to John Grenham:
Another source states:
According to historian C. Thomas Cairney, the O'Dempseys were one of the chiefly families of the Ui Failghe who in turn were a tribe from the Dumnonii or Laigin who were the third wave of Celts to settle in Ireland during the first century BC.

Descent

An Ó Diomasaigh genealogy records the following:
Flann m. Máel Ruanaid m. Cellaich m. Máel Augra m. Conchobuir m. Áeda m. Tomaltajich m. Flaind m. Díumasaich m. Congaile m. Forannáin m. Congaile m. Máel h-Umai m. Cathail m. Bruidge m. Nath Í m. Rosa Failgi.
The final person may be identical with Failge Berraide, a king of the Uí Failghe and of Laigin descent.

Dempseys in the annals

The Irish annals list a number of members of the family:
  • 789: Áedh was slain by Óengus son of Mugrón, king of Uí Failghe, in the oratory of Kilclonfert.
  • 1141: Donnchadh, son of Goll Gaibhle, i.e. Ua Conchobhair Failghe, was killed by the Uí Failghe themselves, i.e. the Clann-Maelughra.
  • 1161: Domhnall, son of Conghalach, son of Cuaifne Ua Conchobhair Failghe, Tanist of Uí Failghe, was slain by the Clann-Maelughra.
  • 1164: Maelseachlainn Ua Conchobhair Failghe, was slain by the Clann-Maelughra.
  • 1193: Diarmait, son of Cubrogam Ua Diumasaigh, chief of Clann-Mailighra and king of Uí Failghe for a long time, died.
  • 1383: Dermot O'Dempsy, Lord of Kinel-Maoilughra, was slain by the English.
  • 1394: Thomas O'Dempsy, heir to the lordship of Clann-Maoilughra, was slain by the English.

Other Dempsey families

An unrelated family, rendered in Irish as Mac Diomasaigh, are found in County Antrim and its neighbouring counties.

Bearers of the name

Notable people with the surname Dempsey include:
As a given name:
Fictional Characters: