The death has occurred at the age of 82 of Prof Brian O Cuiv, a leading Celtic scholar and the author of many works on the Irish language and its history.
He was married to Emer de Valera, daughter of the former President, Eamon de Valera, and was the father of the Fianna Fail TD for West Galway, Mr Eamon O Cuiv.
Prof O Cuiv was a former director and senior professor of the School of Celtic Studies of the Dublin Institute of Advanced Studies.
He began his academic career in St Patrick's College, Maynooth, before moving to University College Dublin in 1953. He was appointed professor of classical Irish language and literature in 1960.
His publications include The Irish of West Muskerry, Co Cork (1944), Irish Dialects and Irish-speaking Districts (1951), Literary Creation and Irish Historical Tradition (1964) and A View of the Irish Language (1969). He was a member of the Royal Irish Academy.
Prof O Cuiv is survived by his wife and children, Nora, Maire, Caitriona, Vivian, Shan, Eamon, Brian, Ruairi and Eoin.
Funeral arrangements will be announced later.