Plas Newydd, Llangollen Plas Newydd, Llangollen Plas Newydd (, ; "new hall" or "new mansion") is a historic house in the town of Llangollen, Denbighshire, Wales, and was the home of the Ladies of Llangollen, Lady Eleanor Butler and Sarah Ponsonby, for nearly 50 years. Today, it is run as a museum by Denbighshire County Council. Plas Newydd is notable as the home where two Irish ladies, Lady Eleanor Butler and Miss Sarah Ponsonby (the Ladies of Llangollen) eloped and set up house together in the late 18th century, scandalising contemporary British society. Plas Newydd was originally a five-roomed stone cottage, but over
William Ponsonby, 2nd Earl of Bessborough 1765 jointly with Thomas Robinson, 1st Baron Grantham, until he resigned in 1766, his initial offer to resign having been refused. Upon William Ponsonby's death on 11 March 1793 his son, Frederick Ponsonby, succeeded to his titles. William Ponsonby was the son of Brabazon Ponsonby, 1st Earl of Bessborough, and his wife Sarah Margetson, and elder brother of John Ponsonby. On 5 July 1739 William married Lady Caroline Cavendish, eldest daughter of William Cavendish, 3rd Duke of Devonshire, who died in 1760 aged 40. They had three surviving children: Parkstead House, Roehampton, was built in 1750 for William Ponsonby, and