Eóganachta

The Eóganachta (or Eoghanachta), by tradition founded by Eógan, king of Munster, the firstborn son of the semi-mythological third-century king Oilill Ollum, was an Irish dynasty centred around Cashel which dominated southern Ireland from the 5th to the 16th century. Eógan had a younger brother, Cas, who is said to have originated the rival Dál gCais dynasty of Ireland. The Dál gCais displaced the increasingly divided Eóganachta during the course of the 10th century.

Ó Scannail of Munster must have been a sept of some significance, for it is recorded that in 1014, Eocha, son of Dunadbach, Chief of Clann Scannail, and Scannail son of Cathal, Lord of Eoghanacht Locha Léin (the most powerful clan grouping in Munster at the time), were killed at the battle of Clontarf.

Eóganachta surnames include MacCarthy, O'Sullivan, O'Mahony, O'Donoghue, O'Moriarty, O'Keefe, O'Callaghan and Scannell. Also included are the Ui Fidgeinte (e.g. the O'Donovans), non-subject allies of the Eoganachta (Cashel) who may have originally belonged to the Erainn as some claim, although it is just as likely the Uí Fidgeinti were a more senior branch of the Eoganachta excluded from the innovative politics at Cashel.

The septs or branches of the Eóganachta and some of their more notable members include:

• Eóganacht Chaisil of Cashel
  • Feidlimid mac Cremthanin (died 847)
  • Cormac mac Cuilennáin (died 908)
• Eóganacht Áine
• Eóganacht Airthir Cliach
  • Fergus Scandal mac Crimthainn (died 582)
• Dál gCais
  • Brian Boru (died 1014)
• Uí Fidgeinti
• Eóganacht Glendamnach
  • Cathal Cú-cen-máthair mac Cathaíl (died 665 or 666)
• Eóganacht Locha Léin
  • Áed Bennán mac Crimthainn (died between 619 and 621)
• Eóganacht Maige Geirginn. The plain of Circinn is thought to be the area of Angus and the Mearns in Scotland.
  • Óengus I of the Picts (died 761)
• Eóganacht Raithlind