William Bentinck was from a noble Dutch family, the son of Henry Bentinck of Diepenheim. He began his lifelong service to King William III, Prince of Orange, as a page of honour and played a crucial role in the plan to install the Prince on the throne of England. Shortly before the coronation of William and Mary he was created Baron Cirencester, Viscount Woodstock and Earl of Portland. A highly skilled diplomat he was a key figure in most of the important political negiotiations of King William III's reign, and served with distinction in several military campaigns. He was made a Knight of the Garter in 1697. He resigned his royal offices in 1699 and was succeeded as a confidant to the new sovereign, Queen Anne, by the Duke of Marlborough.