The O’Dalaigh are one of many of the clans of Ireland that trace their heritage to a single common ancestor. The accepted O’Dalaigh ancestral records beginning at the earliest reliable historical period center on King Niall of the Nine Hostages. Niall (pronounced Nall) reigned as Ireland’s high king from A.D. 379 to 405.
The earliest recording of the name was Cuchonnacht O’Dalaigh, who lived in Teffia, in what is now the County of Westmeath. Being noted for his learning, he was called “Cuchonnacht na Sgoile,” meaning “Cuchonnacht of the School.” He died in the year 1139. The “O” prefixed to the name “Dalach” or “Dalaigh” signifies grandson or male descendant of Dalach in contrast to the prefix Mac or Mc which would mean son of the ancestor specified.
The modern Anglicised versions of the ancient Gaelic family name Ua Dalaigh or O’Dalaigh, pronounced “O’Dhaulee,” came about as a result of tyrannical laws, designed by the English rulers, which outlawed Gaelic names and customs as a means of penalizing the Irish people into a state of subjugation.
Beginning with the reign of the English King Edward IV (1465), the law demanded that every Irishman living within the territory known as the “Pale” take an English name and comply with other English customs or forfeit his possessions. Most families resisted and it wasn’t until the close of the Seventeenth Century, after constant persecution and ridicule that the Gaelic forms nearly dissapeared.
In many cases the Anglicised forms were actually closely related to the basic Gaelic surnames minus the “Macs” or the “O’s” as in the case of the name Daly. The final doom of the Gaelic surnames came as a result of the widespread establishment of the English language among the Irish. This circumstance caused the English form of names to be taken for granted and considered as natural. In recent times, the Gaelic original has been re-adopted by some of the families. This trend back to the Gaelic will naturally spread as the ancient language gradually resumes its old dominant position in Ireland.
The common definition of the O’Dalaigh surname today is, “deriving from Dalach meaning ‘one who is present at assemblies'; the root word is Dail, now the official title of the parliament of the Republic of Ireland”. A connection is also possible to the long tradition of scholarship and poetic achievement associated with those who bear it, since the ollamh of Gaelic Ireland had a place of honor at the tribal dail as a man of learning and a poet.
Other evidence points to an even older more significant meaning, based on the claim by the pagan Irish that they were offspring of their gods. This evidence is found on several Ogham stones which contain the oldest known form of Irish writing.
An example from the Gowran Stone; DALLO MAQA MUCORI MAQI ERACIAS MAQI LI and one from the Dunbell Stone of Kilkenny BRANITTOS MAQI DECARI DDALLOS. These inscriptions appear to invoke either pagan gods or mythological figures with names similar to the ancestral “Dalach”. A third ogham, Monataggert II further specifies the Dalach (Dalagni) as sons of the eponymous ancestor (Dali).
In many cases the mythological ancestor was female. DALAG N I MAQ I DALI From this evidence and other data associated with times of antiquity in Ireland, it would appear that there are reasonable grounds for assuming the family name “O’Dalaigh” has a godly or mythological significance.Indeed, it provides a more logical probable meaning of the name O’Dalaigh than the more popular versions built almost entirely on definitions given in modern dictionaries for supposed parts of the family name.
Almost without exception the armorial motto of the O’Dalaigh has been featured as “Deo et Regi Fidelis”. However, the O’Dalaigh had used a Gaelic motto prior to the adoption of “Deo et Regi Fidelis” by those O’Dalaigh who wished to signify their loyalty to the reigning English monarchs. Around the turn of the century, an Irish motto: “Laudir Agus Mir”, meaning Swift and Strong, was found to have existed among the O’Dalaigh’s of Galway and its origin being very old. Indeed, “Laudir Agus Mir” is clearly descriptive of the O’Dalaigh crest whereas the usual one “Deo Et Regi Fidelis”, i.e. Faithful to my God and King is neither descriptive of the crest nor of the (mostly) disloyal family of O’Dalaigh’s.
From “History of the O’Daly’s, The Story of the Ancient Irish Sept, The Race of Dalach of Corca Adaimh” by Edmund Emmett O’Daly (Chicago, 1932).