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,
William Pitt, 1st Earl of Chatham entire tenure of office. Chatham rarely saw any of his colleagues though they repeatedly and urgently pressed for interviews with him, and even an offer from the King to visit him in person was respectfully declined. While his gout seemed to improve, he was newly afflicted with mental alienation bordering on insanity. Chatham's lack of leadership resulted in an incohesive set of policies. Chatham dismissed his allies Amherst and Shelburne from their posts, and then in October 1768 he tendered his own resignation on the grounds of poor health, leaving the leadership to Grafton, his First Lord of the Treasury.