Mac Diarmada

Mac Diarmada is the original Irish Gaelic form of the surname McDermott, meaning "son of Diarmaid." It is a prominent Irish surname and the name of the ruling dynasty of Moylurg, a medieval kingdom in Connacht that existed from the 10th to 16th centuries.

Etymology

The surname Mac Diarmada derives from the Gaelic patronymic prefix mac ("son of") and the personal name Diarmaid, of uncertain meaning. While suggestions include "without envy," the exact etymology remains unknown. The name is linked to Irish legend, as Diarmaid was the lover of Gráinne in the tale The Pursuit of Diarmaid and Gráinne. The root Gráinne itself derives from Old Irish words meaning "grain" or "hatred."

Historical Significance

The Mac Diarmada clan were the rulers of Moylurg, a kingdom in Connacht. The progenitor was Dermot mac Tadhg Mor, 7th King of Moylurg, who reigned from 1124 to 1159. They were vassals and kinsmen of the Ó Conchubhair (O'Connor) kings of Connacht, sharing a common ancestor, Tadg mac Cathal, King of Connacht from 925 to 956. Their power base was McDermott's Castle on Lough Key. Later offshoot septs included the MacDermot Roe family. The kingdom of Moylurg ended in the late 16th century, with the last ruling king, Tadhg mac Diarmata, reigning until 1585. Afterward, the senior MacDermot line faced poverty but continued despite land confiscations following the Tudor conquest of Ireland.

Related Forms and Distribution

Anglicized forms include McDermott, MacDermott, and Dermott. The Manx equivalents are Kermit and Kermode, reflecting Gaelic influence on the Isle of Man. Today, the surname Mac Diarmada and its variants are found primarily in Ireland, especially in counties Roscommon and Leitrim, as well as in the Irish diaspora.

Notable Bearers

• Dermot mac Tadhg Mor (12th century): 7th King of Moylurg, progenitor of the dynasty.
• Tadhg mac Diarmata (16th century): Last ruling king of Moylurg until 1585.

• Meaning: Son of Diarmaid
• Origin: Irish Gaelic
• Type: Patronymic surname
• Usage Regions: Ireland, especially Connacht; also Irish diaspora