Origin of the O'Mahony Clan Name

O’Mahony is a gaelic form of the name Ó Mathghamhna, meaning descendant of Mathghamhain (the Good Calf).  The forefather of the great  Mahoney Clan, Mathghamhain was the son of Cian and Sadhbh, herself daughter of the great Brian Boru.

The O'Mahonys came to the very south west of Ireland in the 6th and 7th centuries and belonged to the clans of the Eóganachta. They lost lands to the MacCarthys when they arrived here in the 12th century, and later to the O'Driscolls and the O'Donovans, but these clans were on good terms and conferred on French and Iberian fleets the right to fish and salt their catch at bases. Until the 15th century they were prosperous and building of religious houses and tower houses was common.

O'Mahony Clan

The Mahoney Chiefs were referred to as “Rithe na Naoi bFonn” which means Kings of the Nine Territories. They built many castles in County Cork, near Mizen Head, among those, Rosbrin, Dunmanus and Dunlough, at Mizen Head, one of the oldest Norman castles in Ireland.

The O'Mahony's were among those who fought and died a the Battle of Clontarf in 1014.

Later their power declined due to British intervention and the events at Kinsale in 1602. Their leader at this time Donal O'Mahony escaped forfeiture due to his young age.

The O'Mahony crest includes three lions thought in Ireland to represent the lions season, ie before the arrival of summer, in colours that signify strength, generosity and loyalty. The lower left quarter contains a chevron for protection and the serpent fr good healtyh, longevity and fertility.