The sale will take place on the premises on October 21 in a 500-lot auction with an estimate of more than €1m.
Formerly the principal seat of the Earls of Bantry, the house was owned and run by the late Egerton Shelswell-White and his wife, latterly with the help of their eldest daughter Sophie Shelswell-White, who has been general manager since 2010.
"It has been a very difficult decision, but also an exciting and stimulating one," she said. "The funds from the sale will inject a new energy into the house and also into us, as a family. Many of the objects in the sale are of museum quality and need to be expertly cared for, a luxury we could only afford with great difficulty."
Items in the sale include many collected by Richard White, the second Earl of Bantry (1800-68), such as the French tapestries that adorn the walls of several rooms. One of the two Gobelins panels is said to have hung in the Palace of Versailles and there is a particularly beautiful rose-coloured set of Aubusson tapestries, which are said to have been made by order of Louis XV for Marie Antoinette on her marriage to the Dauphin of France.
Among the furniture is a Russian household shrine which contains 15th and 16th century icons and an impressive pair of William Kent-style console tables, while the paintings include a pair of portraits from the studio of Allan Ramsay of George III and Queen Charlotte, presented by the monarch to the First Earl of Bantry on his elevation to the peerage.