Earl of Londonderry extinct on the death of his great-grandson, the fourth Earl, in 1714. The second creation came in 1726 in favour of the soldier and politician Thomas Pitt, 1st Baron Londonderry. He had already been created Baron Londonderry in 1719 and was made Viscount Gallen-Ridgeway at the same time as he was granted the earldom, also in the Peerage of Ireland. He was the husband of Lady Frances Ridgeway, daughter and heiress of the fourth Earl of the first creation. A member of the prominent Pitt family, he was the uncle of William Pitt, 1st Earl of Chatham. His younger son,
Duke of Argyll Morvern, and Tiree" for his services to William of Orange. His son, the 2nd Duke, was created Baron Chatham and Earl of Greenwich in 1705 as a reward for his support for the Act of Union and further elevated to the title Duke of Greenwich in 1719. Upon his death his Scottish titles passed to his brother and the English titles became extinct. The 5th Duke sat as a member of parliament for Glasgow until his father's accession to the Dukedom in 1761 disqualified him from representing a Scottish seat. He then became the member for Dover until 1766, when