Sir John Grenville, 1st Earl of Bath, 1628-1701
He served the King's cause as a soldier, privateer and conspirator, then secured the allegiance of General Monck to bring about the Restoration.
Born at Kilkhampton in Cornwall in August 1628, John Grenville was the third son of Sir Bevil Grenville and his wife Grace, daughter of Sir George Smith. By 1641, both John's elder brothers had died and he became heir to his family's extensive estates in Cornwall and Devon. He was educated at home but in 1642, his education was interrupted by the outbreak of civil war.
At the age of fourteen, John held a commission in his father's regiment, which fought for the King under Sir Ralph Hopton in south-western England. When Sir Bevil was killed at the battle of Lansdown in July 1643, Cornish soldiers mounted John upon his father's horse and declared their allegiance to him as head of the Grenville family. He was knighted by King Charles I after the capture of Bristol in August 1643 and served with the King's Oxford army in the Lostwithiel campaign in 1644. Grenville was severely wounded at second Newbury, where he was found lying unconscious among the dead. In 1645, he was appointed a gentleman of the bedchamber to Charles, Prince of Wales and remained one of Charles' closest friends and advisers.

After the defeat of the Royalists in the English Civil War, Grenville accompanied Prince Charles to Scilly, Jersey and Paris. In February 1649, after the execution of his father, Charles appointed Grenville governor of the the Scilly Isles. During 1649-51, Grenville directed Royalist privateers from Tresco and St Mary's in a lucrative campaign against English and Dutch merchantmen to raise prize money for Charles II's court-in-exile. A Dutch fleet under Lieutenant-Admiral Tromp was forestalled from attacking Grenville's base when the Commonwealth sent an invasion force under the generals-at-sea Blake and Ayscue in April 1651. Combined land and sea operations against the Royalists quickly secured the island of Tresco. Grenville withdrew into Star Castle on St Mary's, which was besieged and bombarded into submission. On 23 May, Grenville surrendered to Blake under generous terms.
After a brief imprisonment at Plymouth, Grenville was given leave to join Charles in exile but chose instead to remain in England. He married Jane Wyche, daughter of a wealthy London merchant, in October 1652 and became a leading representative of the King's party in Cornwall and the West. During 1654, Grenville was associated with the conspirators of the Action Party and plotted to seize Plymouth and Pendennis Castle. However, he was arrested in February 1655 in the aftermath of a premature uprising by western Royalists in the build-up to Penruddock's Uprising. In 1659, Grenville was a member of the Great Trust and Commission. Although summoned to answer charges before the Council of State when the government infiltrated the Trust's conspiracies, Grenville was released on parole.

Grenville's greatest service to the Royalist cause was in acting as an intermediary between the King and General Monck, who was his second cousin. He first approached the General in 1658 through Monck's clerical brother Nicholas, whom Grenville had appointed to the church living at the Grenville estate of Kilkhampton. Grenville's clandestine negotiations with Monck continued through 1659 and culminated in a secret meeting at St James's Palace in March 1660, during which Monck pledged his allegiance to the King. Grenville carried Monck's message of loyalty to Charles at Brussels and returned to deliver Charles' manifesto the Declaration of Breda to Parliament on 1 May 1660.
Grenville was richly rewarded for his services in securing the Restoration and became the most powerful magnate in the West Country. Among other honours, he was created first Earl of Bath, warden of the Stanneries, lord-lieutenant of Cornwall and governor of Plymouth. He continued his loyal service to Charles II and was present at the King's deathbed conversion to Catholicism in 1685.
Despite losing influence upon the succession of James II, Bath commanded an infantry regiment against the Duke of Monmouth during Monmouth's Rebellion of 1685. When William of Orange invaded England in 1688, however, Bath changed his allegiance. He made no attempt to defend Exeter and surrendered Plymouth to William's forces. Under William III, Bath added the lieutenancy of Devon and the governorship of the Isles of Scilly to his offices. However, he was disappointed when William granted the earldom of Albemarle to a favourite in 1697, a title claimed by Bath through his connection to the Monck family.
His final years were spent in a bitter legal dispute over the Albemarle estate, which almost bankrupted him. Two weeks after his death in August 1701, his son and heir Charles Grenville shot himself, apparently overwhelmed by the debts he had inherited. Father and son were buried on 22 September 1701 in the family vault at Kilkhampton.
Sources:
Peter Gaunt, The Cromwellian Gazetteer, (Stroud 1987)
G. Ridsdill Smith & M. Toynbee, Leaders of the Civil Wars 1642-48 (Kineton 1977)
Victor Stater, John Grenville, first earl of Bath, Oxford DNB, 2004
David Underdown, Royalist Conspiracy in England 1649-60 (New Haven 1960)