Leeds, Duke of, Thomas Osborne (1631-1712), was the son of a Yorkshire baronet. In 1661 he became M.P. for York, and was a staunch upholder of Church and king. His principles brought him preferment and the favour of the king, and in 1674 he was made Lord High Treasurer and Earl of Danby. He acted as a go-between to Charles II. and Louis XIV., and in 1678 was impeached on this account by the Commons, who kept him in the Tower till 1683, notwithstanding the king's pardon. Not in favour with James II., he joined in inviting William III., and was made Marquis of Carmarthen and President of the Council, being in 1694 advanced to the Dukedom of Leeds. The next year he was again impeached for taking bribes, and in 1699 retired from public life, though he appeared again in 1710 to speak in defence of Dr. Sacheverel.