This branch of the Shelley family descends from John Shelley-Sidney, the only son of the second marriage of Sir Bysshe Shelley, 1st Baronet, of Castle Goring by Elizabeth Jane, daughter of William Perry and Elizabeth, daughter and heir of the Hon. Thomas Sidney, fourth son of Robert Sidney, 4th Earl of Leicester. In 1799 he assumed by Royal licence the additional surname of Sidney on succeeding to the estates, including Penshurst Place in Kent, of his maternal grandmother. In 1818 he was created a Baronet, of Penshurst in the County of Kent, in the Baronetage of the United Kingdom. His son and heir apparent, Philip Sidney, represented Eye in the House of Commons. In 1835, fourteen years before succeeding his father in the baronetcy, he was raised to the Peerage of the United Kingdom as Baron De L'Isle and Dudley, of Penshurst in the County of Kent. The title derived from the fact that the title of "Viscount De L'Isle" had been held by his ancestors the Earls of Leicester, but had become extinct along with the earldom in 1743. The title of "Dudley" came from the fact that Robert Sidney, 1st Earl of Leicester was the nephew of Robert Dudley, 1st Earl of Leicester, the fifth son of John Dudley, 1st Duke of Northumberland, who was as well Viscount Lisle by right of his mother. Lord De L'Isle and Dudley discontinued the use of the surname Shelley. His grandson, the fifth Baron, notably served as Mayor of Chelsea and was a member of the London County Council. His son, the sixth Baron, was a prominent Conservative politician and served as Secretary of State for Air from 1951 to 1955. In 1956 he was created Viscount De L'Isle, of Penshurst in the County of Kent, in the Peerage of the United Kingdom. Lord De L'Isle later served as Governor-General of Australia. In 1965 he also succeeded his kinsman as ninth Baronet of Castle Goring. the titles are held by his son, the second Viscount, who succeeded in 1991. The family seat is Penshurst Place, near Tonbridge, Kent. Close to it is the parish church of St John the Baptist where the Sidney Chapel houses many memorials to the family.
Shelley-Sidney Baronets, of Penshurst Place (1818)
Sir John Shelley-Sidney, 1st Baronet
Sir Philip Sidney, 2nd Baronet
Barons De L'Isle and Dudley (1835)
Philip Sidney, 1st Baron De L'Isle and Dudley
Philip Sidney, 2nd Baron De L'Isle and Dudley
Philip Sidney, 3rd Baron De L'Isle and Dudley
Algernon Sidney, 4th Baron De L'Isle and Dudley
William Sidney, 5th Baron De L'Isle and Dudley
William Sidney, 6th Baron De L'Isle and Dudley
Viscounts De L'Isle (1956)
William Sidney, 1st Viscount De L'Isle
Philip Sidney, 2nd Viscount De L'Isle
The heir apparent is the present holder's only son the Hon. Philip William Edmund Sidney.