An urgent appeal has been made to the Taoiseach to prevent the "imminent collapse" of Dysart Castle near Thomastown, Co Kilkenny - the childhood home of the 18th-century philosopher, George Berkeley.
homeA major figure in the history of ideas, Berkeley is best known for his empiricist philosophy, which holds that everything save the spiritual exists only in so far as it is perceived by the senses.
A fellow of Trinity College, Dublin, he was consecrated as Bishop of Cloyne in 1734 and took a seat in the Irish House of Lords in 1737. Credited by Alexander Pope with "ev'ry virtue under heav'n", Berkeley spent some time in America and gave his name to the Californian city of the same name.
In the last month a large new crack has appeared in the wall of the castle, which was being conserved with the aid of funds from Kilkenny County Council acting for the Department of the Environment, and the private resources of the present owner, Mr Ramie Leahy.
The archaeological complex around Dysart Castle shows evidence of a ninth-century church which may have been extended in the 12th century by the Augustinian Order.
The castle keep dates from 1460; the adjoining Berkeley House dates from about 1650. And a Georgian farmhouse is currently being restored.
People have lived at Dysart "for about 2,000 years", according to Mr Leahy, making it one of the longest continuously inhabited sites in Ireland.
Mr Leahy, who is a painter, bought the complex of buildings in 1976 when he was an art teacher attached to Thomastown VEC and has been raising funds for conservation and restoration ever since.
His ambition is to have the castle and Berkeley House restored and employed as a library or place of reference for students of Bishop Berkeley's philosophy.
While conservation was moving ahead slowly - the late President Éamon de Valera sought funds for the restoration of Dysart Castle in the United States in the early half of the last century - Mr Leahy said the issue had now become urgent.
Fund-raising aimed at getting a contribution of £50,000 from the city of Berkeley has proved fruitless, and Mr Leahy said that if work was not now carried out urgently, "the castle will fall down".
He has written a personal appeal to the Taoiseach which was delivered by Mr John McGuinness, TD for Carlow-Kilkenny, who is supportive of the project.
The International Berkeley Society - an organisation of nearly 200 academics, informed citizens and public servants in 19 countries has also supported the conservation work and a study has been undertaken by the University of California, Berkeley.However for Mr Leahy the future is stark. Without urgent work he is convinced the castle will fall and the work he has doen for more than 25 years will be lost.