Hans Willem was the son of Bernard, Baron Bentinck of Diepenheim and descended from an ancient and noble family of Guelders and Overijssel. He was appointed first page of honour and chamberlain. When, in 1675, Prince William was attacked by smallpox, Bentinck nursed him assiduously, and this devotion secured for him the special and enduring friendship of William. From that point on, Bentinck had the Prince's confidence, and in their correspondence William was very open.
Communicator
In 1677 he was sent to England to solicit for Prince William the hand of Mary, daughter of James, Duke of York and future King of England. He was again in England on William's behalf in 1683 and in 1685. Later, in 1688, when William was preparing to assist in the overthrow of James including an invasion by Dutch troops, Bentinck went to some of the German princes to secure their support, or at least their neutrality. He had also been, since 1687, a medium of communication between his master and his English friends. Bentinck superintended the arrangements for the invasion, including raising money, hiring an enormous transport fleet, organising a propaganda offensive, and preparing the possible landing sites, and also sailed to England with Prince William.
Bentinck's main work was of a diplomatic nature. In 1690 he was sent to The Hague to help solve the problem between William and the burgomasters of Amsterdam. He was caught up in the corruption scandal concerning the East India Company in 1695; the board was losing its monopoly under pressure from a New Company and was engaging profusely in bribery in an attempt to renew its charter. He was however cleared in the matter. Having thwarted the Jacobiteplot to murder the King in 1696, he helped to arrange the peace of Ryswick in 1697. In 1698 he was ambassador to Paris for six months. While there, he opened negotiations with Louis XIV for a partition of the Spanish monarchy, and as William's representative, signed the two partition treaties.
Resignation and land gifts
William Bentinck had, however, become very jealous of the rising influence of another Dutchman, Arnold van Keppel, and, in 1699, he resigned all his offices in the royal household. He did not forfeit the esteem of the King, who continued to trust and employ him. Portland had been loaded with gifts, and this, together with the jealousy felt for him as a foreigner, made him very unpopular in England. He received 135,000 acres of land in Ireland, and only the strong opposition of a united House of Commons prevented him obtaining a large gift of crown lands in North Wales. For his share in drawing up the partition treaties he was impeached in 1701, but the case against him did not proceed. He was occasionally employed on public business under Queen Anne until his death at his residence, Bulstrode Park in Buckinghamshire. Portland's eldest son Henry succeeded him as earl, and was granted the titles of Marquess of Titchfield and Duke of Portland in 1716.
Codex Bentingiana
While living in Holland, Bentinck maintained a garden boasting many botanical rarities. Illustrations of these plants were collected under the name Codex Bentingiana. This work has since disappeared from the botanical scene.
Family
Lord Portland was married twice. On 1 February 1678, he married his first wife, Anne Villiers, daughter of Sir Edward Villiers and his wife Lady Frances Howard, daughter of the 2nd Earl of Suffolk. They had seven children:
Lady Mary Bentinck, who married, firstly, the 2nd Earl of Essex on 28 February 1692 and had one son and two daughters. She married, secondly, Sir Conyers D'Arcy, circa August 1714 and had no issue.
