He was admitted an advocate in Doctors' Commons in London on 28 April 1668 and began practising in the ecclesiastical and admiralty courts. He would remain for the next 15 years, becoming a lawyer of high repute. Through the offices of his father-in-law, Sir Charles Cotterell, he was appointed chancellor of the diocese of Rochester in 1671 by its bishop, John Dolben, the future archbishop of York, and benefited much from 'the friendship and patronage of that great and good man'. In 1683 he was appointed Judge Advocate of the Fleet by Lord Dartmouth, George Legge, in an expedition to evacuate the British colony at Tangier, where he was to act as commissioner for settling the leases of the houses between the King and the inhabitants. Samuel Pepys, who was also on the expedition, was unimpressed – "Strange to see how surprised and troubled Dr. Trumbull shows himself at this new work put on him of a judge-advocate; how he cons over the law-martial and what weak questions he asks me about it." Later Pepys calls him "a man of the meanest mind as to courage that ever was born." In 1684, Charles II considered Trumbull as a possible Secretary of State, but he was eventually offered the office of Secretary of War in Ireland, which he turned down. Nevertheless, he was knighted on 21 November 1684, and on 1 February 1685 was made Clerk of the Deliveries of the Ordnance. Through the favour of the Trelawny family, he entered Parliament as MP for the Cornish borough of East Looe 1685–1687. Charles II died a few days later and Trumbull had to relinquish the clerkship when he was sent by James II, against his own wishes, as envoy extraordinary to France. With King James a declared papist and French King Louis XIV persecuting his Protestant subjects, Trumbull, a devout Anglican, was an odd choice for the post, being a zealous opponent of Roman Catholicism, and did much to benefit the condition of the English Protestants in France after Edict of Fontainebleau. In 1686 he was recalled from Paris, and on 15 October was nominated by the king to be appointed Ambassador at Constantinople, where he arrived on 17 August 1687. He remained ambassador until 31 July 1691 when he departed Turkey. Sir William was a Governor of the Hudson's Bay Company from 1696 to 1700 and the Turkey Company from 1696 to 1709. On 3 May 1694 he was appointed a Commissioner of the Treasury, and a year later was made a Privy Counsellor and appointed Secretary of State for the Northern Department. However, he was unhappy in the post, and resigned it on 2 December 1697. He then retired from public life. Trumbull was a friend of both John Dryden and Alexander Pope. Dryden records, in the postscript to his translation of Virgil, that "if the last Aeneid shine amongst its fellows, it is owing to the commands of Sir William Trumbull, who recommended it as his favourite to my care." It was Trumbull who, admiring Pope's translation of the "Epistle of Sarpedon" from the Iliad urged him to translate the whole of Homer's works, and Pope's "Spring" was dedicated to him.
Family life
In 1670, Trumbull married Katherine, daughter of Sir Charles Cotterell, Master of the Ceremonies; she died in 1704, they having had no children. In Scotland in October 1706, he married Judith, daughter of Henry Alexander, the 4th Earl of Stirling. They had two children, Judith and William. Trumbull died on 14 December 1716. He was buried on 21 December at Easthampstead church. His funerary monument in the south transept proclaims that 'he maintained the character of an able statesman'. His son William had an only daughter, who became the wife of the Hon. Martin Sandys, second son of Samuel Sandys, 1st Baron Sandys. She was thus the ancestress of the later marquesses of Downshire.
Letters
Many of Trumbull's letters are in the British Library and in the Record Office, London. Trumbull was on friendly terms with Pierre Bayle and was a mentor to the young Henry St. John, later Viscount Bolingbroke, who may have met his great friend, Pope, through Trumbull.
