Portland, William Bentinck, 1st earl of, 1649–1709, Dutch statesman in England. He was William III's most trusted personal adviser. In 1677 he engaged in negotiating the marriage of William (then prince of Orange) and Mary, daughter of James, duke of York (later James II). With the Glorious Revolution (1688) he went to England with William, was made earl of Portland, and was given extensive estates and honors. Portland fought for William at the battle of the Boyne (1690) and in the War of the Grand Alliance and negotiated the Peace of Ryswick (1697) with France. For negotiating and signing the unpopular Partition Treaties (see Spanish Succession, War of the), he was impeached (1701), but the proceedings were soon dropped.
See M. E. Grew, William Bentinck and William III (1924, repr. 1971).