invasion their power was restricted to
South Offaly, which was subsequently called Ely O’Carroll.
The Ui Cairin or O’Mahers (O Meachair) are of the same stock as
the O’Carrolls, and were lords of Ui Cairin, now the Barony of Ikerrin, in the old
Ely territory in Tipperary. After the Anglo-Norman invasion, Ikerrin was added to Ormond,
but The O’Maher (chief of the sept) was left in control of the territory as tributary
to the Butlers, the Anglo-Norman earls of Ormond, under whom they flourished.
The O’Riordans (O Rioghbhardain) are a branch of the
O’Carrolls of Ely, and probably descend from Rioghbhardan, son of Cucoirne O
Cearbhaill, Lord of Ely, who fell at the battle of Sliabh gCrot in 1058. As late as 1576 a
"Gaven O Rewrdane" was a "freeholder" in Ely O’Carroll, and one
of the most important followers of Sir William O’Carroll. By this time branches had
spread into Leix and Kilkenny, but even earlier the greater portion of the sept had
removed to Cork and Limerick. In 1597 Maurice O’Riordan of Croome was attainted by
the English, his lands being given to a George Sherlocke.
The O’Flanagans (O Flannachain) are of the same stock as the
O’Carrolls of Ely, and were chiefs of a territory known as Cineal Arga, now the
barony of Ballybrit, in southeast Offaly.
The Ui Faitghe
The Ui Failghe, closely related to the Eile, had
probably separated from them by A.D. 516, the year of the defeat of the Eile at Druim
Derge by the Southern Ui Niell. The Ui Failge descend from Failge Berraide, who a few
years earlier had won the battle of Fremainn Mide (A.D. 510). This victory probably
accounts for their being able to remain in the more northerly portion of Offaly while
their cousins, the Eile, were forced to migrate south. The chief families of the Ui
Failghe include the O’Connors of Offaly, the O’Mooneys, MacColgans,
O’Hennesseys, O’Holohans, O’Dempseys and O’Dunnes.
The O’Connors (O Conchobhair) of Offaly were a powerful and
warlike sept of the northeast of what is now County Offaly. They descend from Conchobhar,
son of Fionn, Lord of Offaly, who died in A.D. 979. From their stronghold at Dangan, now
Philipstown, they successfully defended their territory from the English of the Pale (i.e.
County Dublin) for more than 300 years. They were finally dispossessed by the English
about 1550. The O’Mooneys (O Maonaigh) of around Ballymooney in County Offaly are a
branch of the O’Connors.
The Clann Cholgan included the families of MacColgan, O’Hennessy
and O’Holohan. The MacColgans (Mac Colgan) were chiefs of the territory around
Kilcolgan in the extreme northeast of County Offaly. The O’Hennessys (O hAonghusa)
shared the lordship of Clann Cholgan (i.e., their clan-name was applied to the territory
they possessed) with their kinsmen the O’Holohans (O hUallachain). Their territory
comprised the present barony of Lower