Through influence over the Sletty monastery founded by Fiacha mac Breccáin, the family played a role in early Christianity in Ireland.

[8] According to James Frost, the family was likely driven from the lands by the Norman lord Walter de Riddlesford, who became the master of Carlow at around this time.

[7] A poem, written by Maoelin Oge MacBrody (the MacBrodys were the ollaves of the Uí Bairrche), states that after the Mac Gormáin family was driven from its lands a group of them made for Ulster and another made westwards towards Daire Seanleath in Uaithne Cliach (Uaithne Cliach is the modern barony of Owney, in County Limerick).

MacLysaght thought that the man who was chiefly responsible for the choice in the prefix was the Frenchman Chevalier Thomas O'Gorman (1725–1808), who constructed Irish pedigrees after being ruined in the French Revolution.

[8] According to historian C. Thomas Cairney, the MacGormans were one of the chiefly families of the Uí Bairrche who were a tribe of the Erainn who were the second wave of Celts to settle in Ireland between about 500 and 100 BC.

[13] The Uí Bairrche kindred of the Laigin took their name from Dairé Barrach, a son of Cathair Mór, who lived during the 2nd century AD.

In any case, Dairé lived at Dún Ailinne, one of the ancient Gaelic royal sites of Ireland and capital of the Laigin, located in what is now County Kildare.

From here he gained a pupil in Mug Nuadat, ancestor of the Eóganachta, whom he supported in becoming King of Munster in conflict with Conn of the Hundred Battles.

At this time they were very powerful, as one of the sons of Dáire Barrach named Muiredach Mo Sníthech is listed by the 5th century poet Laidcenn mac Bairchid, as a King of Leinster and may have possibly even ruled at the Hill of Tara.

Indeed, they only returned when Eochaidh Guinech of the Uí Bairrche killed his maternal grandfather Crimthann mac Énnai, King of Leinster in 483.

Fiacha was a bard and his uncle Dubthach maccu Lugair was the Chief Ollamh of Ireland; the conversion of the two helped to reconcile elements of native Gaelic tradition with Christianity.

The mother of Colm Cille (Columba of Iona) named Eithne also descended from Ailill Mór mac Breccáin.

Later on, in the 7th century, Aodh, the Abbot of Sleaty was the man who requested the writing of the Vita sancti Patricii (Life of St. Patrick), contained in the Book of Armagh.

The kindred still had a prominent position; the mother of Diarmait mac Cerbaill (died 565), the last High King of Ireland inaugurated according to the traditional Gaelic pagan rites, was Corbach, daughter of Maine, a member of the Uí Bairrche.

A notable king of the age was Cormac mac Diarmata, whom many Christian hagiographies associated with their rivals the Uí Cheinnselaig or the Osaraighe; such as that of Abbán and Cainnech of Aghaboe; paint him as pillaging monasteries and the like.

Suibhne's brother Failbe eventually married Eithne, daughter of Crundmael mac Rónáin, King of the Uí Cheinnselaig.

Around the area of Uí Bairrche and the Laigin more generally, we know that the Vikings pillaged Dún Másc in 842 and established a settlement at Loch Garman (later known as Wexford), close to Bargy.

Just prior to the Norman invasion of Ireland, a number of Mac Gormáin are found to have been in prominent clerical roles as writers and teachers.

Riddlesford, who took over as a master at Carlow, had married the daughter of a bastard son of a king Henry I of England which left him in a prominent position among his own people.

As part of a plan to win back the kingdom, Briain Ruadh went to Thomas de Clare (a Norman), close friend of king Edward I of England and attempted to enlist his support in return for land to colonise.

It must be remembered that, during Domhnall's life, cattle was the main element of the pastoral economy; the Gaelic kingdoms did not mint their own coinage.

His nephew, Donnchadh Ó Briain, who had long since joined the English service, became Baron Ibrackan (named for the territory associated with the Mac Gormáin).

During the reign of the Stuart dynasty king James I of England, the Mac Gormáin held lands from Tadhg Caech Mac Mathghamha, Lord of West Corcavaskin, specifically named lands in their hands include; Clooncullin, Kilmacduane, Ballynagur, Moyarta, Knockerra, Clohanbeg, Clohamore and Cahermurphy.

At Drom Díogais (Drumdigus) we find lands held by Tadhg Mac Gormáin (died 1630) also the owner of Tulach an Chrainn (Tullycrine) and known for his wife's association with a certain "holy well” at Kilmihil.

An ambitious raid on the castle, looking to take livestock, was led by Edmond O'Flaherty from the Aran Islands, joined by men from Connemara (what used to be Iar Connacht).

After the victory of the Cromwellian side during the conflict, certain Catholics in other parts of Ireland were “transplanted” to Connacht (which then included County Thomond), to make way for the Protestant English incomers on better lands.

This included the Norman-descended Catholics, Annie and Martha Eustace who were; according to the Act of Settlement 1662; transplanted into the lands of what was Mac Gormáin territory in Dromelihy.

Family tradition; especially among the diaspora in North America where some descendants ended up; states the land was confiscated during Cromwellian times and this may have simply been a confirmation of an earlier fact.

During the Penal Laws, Catholics were persecuted and blocks put in their way to stop them from owning significant tracts of land and generally building themselves up in society.

Indeed, along with William Smith O'Brien and Thomas Francis Meagher, he visited the newly formed Second French Republic in 1840 and returned with the Irish Tricolour which later became the national flag after 1922.