The O’Kelly surname is the Anglicized form of the Gaelic name O’Ceallaigh. Before the Norman invasion of Ireland in 1169, several branches of the Kelly clan held power in different regions of Ireland.
Like many other Irish clans, they lost much of their power and lands in the 12th century. However, Kelly is one of the most common names in Ireland in modern times (the statistics are in our article on the Kelly family name).
But let’s take a look at what’s known of their early history.
The Uí Maine Kellys
In Connacht, the Kellys were part of the Uí Maine, a group of powerful families whose territory covered much of what is now County Galway and County Roscommon.
The Kellys were one of the leading septs (sub-groups) of the Uí Maine. This family produced many distinguished chiefs, among them Tadhg Mór Ó Ceallaigh.
Tadhg Mór Ó Ceallaigh, Died 1014
Tadhg Mór Ó Ceallaigh is particularly famous for his actions in the Battle of Clontarf in 1014, one of the most famous and significant battles in Irish history.
The battle pitted the forces of Brian Boru, the High King of Ireland, against a coalition of Irish and Viking forces led by the King of Leinster, Máel Mórda mac Murchada, and the Viking King of Dublin, Sitric Silkbeard.
Tadhg Mór Ó Ceallaigh was a commander in the army of Brian Boru. Although Brian’s forces won the battle, Brian Boru himself had been slain in his tent by one of the enemy leaders, Brodir of the Isle of Man.
As the fighting was coming to an end, Tadhg Mór was fatally wounded on the battlefield. But as he was dying, he killed Brodir, thus avenging Brian.
It’s worth noting that this account comes from later sources and has likely been embellished over the centuries. Still, Tadhg Mór Ó Ceallaigh is revered as a heroic figure in the history of the Kelly clan.
The Breagh Kellys
Another O’Cealleagh family were lords of Breagh, a territory covering parts of County Meath and North Dublin.
These Kellys were a branch of the Ui Neill dynasty (the O’Neills).
Other Kelly Families
These two groups of Kellys operated independently of each other, and it’s likely that many other families in Ireland also adopted the name Kelly (Ó Ceallaigh) independently.
So, the history of the Kellys is really the history of several distinct families, each with their own stories and power dynamics.
Colla da Crioch – Ancestor Of The Kelly Clan
Some scholars say that the Kelly clan descends from Colla da Crioch, a king in the 4th century. Legend has it that he was one of three brothers known as the Three Collas:
- Colla Uais
- Colla da Crioch
- Colla Menn
“Colla” means strong man, and “Colla da Crioch” means “Colla of the two countries”. The two countries were Ireland and Scotland.
The brothers’ uncle Fiacha was High King of Ireland. When the brothers killed him in battle, Colla Uais took the title for four years.
But the trio were defeated by Fiacha’s son, Muireadach, who banished them to Scotland. After some years, Muireadach let them return and command his armies.
If you’re wondering why the son was so forgiving towards the men who killed his father, there was a prophecy that stayed his hand. The legend was that if someone killed the brothers, his descendants would not become king. That’s why Muireadach let them live – but made them work in his service.
Muireadach sent the three brothers to conquer territory in Ulster. The story goes that Fergus, the King of Ulster, killed Colla Menn before he himself was killed by Colla Da Crioch.
The conquered lands became a new kingdom called Airghialla (Oriel) that covered parts of Derry, Tyrone, west Monaghan, and Fermanagh. Colla da Crioch was the first king of Airghialla.
The descendants of the Collas established many of the great clans of Ireland. Some lines are more accepted than others! The Ui Maine Kellys are said by some to be descendants of Da Crioch.