Prior to the land reforms of the late 1500s most Ó Nualláin descendants in the Co. Carlow area were already giving their family name as O Nolan.

With the land reforms, they were forced to drop the “O” prefix.  At this time some Ó hUllacháins in Counties Galway and Mayo and also some Ó hUltacháins in Fermanagh also adopted the “Nolan” family name. To find a credible explanation as to why this happened we have to we have to reach far back into folk memory as recorded by the Irish Annalists and also to take note of what modern archaeologists have discovered about an early Celtic tribe refered to by historians as the Menapii.

Bottom line, I believe that, until the time Gaelic families were forced to adopt English-sounding family names due to land reforms, they retained the ancient memory of being descend ed from “the famous one” (Ó Nualláin) and wanted to retain that memory in their family name. The famous ancestor of which they had memory, I believe, was Ugaine MOr, the first historically recognized Ard Ri of Irleand reigning from 331 to 301 BC.

Gaelic Meaning of Family Name

Ó NUALLÁIN – Irish Gaelic surname
where  “NUAL” means“FAMOUS, RENOWNED, NOBLE” , 
“ÁIN” is a diminutive suffix
and  the whole means descendant of “NUALLAN”