“ LONDONDERRY, CHARLES WILLIAM STEWART (VANE) , 3rd Marquess of (1778–1854) , British soldier and diplomatist, was the son of the 1st marquess by a second marriage with the daughter of the 1st Earl Camden. He entered the army and served in the Netherlands (1794) , on the Rhine and Danube (1795) , in the Irish rebellion (1798) , and Holland (1799) , rising to be colonel; and having been elected to parliament for Kerry he became under secretary for war under his half-brother Castlereagh in 1807. In 1808 he was given a cavalry command in the Peninsula, where he brilliantly distinguished himself. ”

“ In 1814 he was made a peer as Baron Stewart, and later in the year was appointed ambassador at Vienna, and was a member of the important congresses which followed. In 1822 his half-brother’s death made him 3rd marquess of Londonderry, and shortly afterwards, disagreeing with Canning, he resigned, being created Earl Vane (1823) , and for some years lived quietly in England, improving his Seaham estates. ”