Dillon, Arthur (1670–1733), Jacobite general in the French service, was born in Co. Roscommon, the third son of Theobald Dillon (qv), 7th Viscount Dillon of Loughglinn, Co. Roscommon, and lieutenant-colonel in the army of James II (qv), and his wife Mary, daughter of Sir Henry Talbot of Mount Talbot, Co. Roscommon. In 1688 his father raised the Regiment of Dillon which was sent to France two years later as part of Lord Mountcashel's brigade, in exchange for veteran French regiments sent to Ireland. Arthur Dillon was commissioned on 1 June 1690 as a colonel in the French army and given command of the Regiment of Dillon. The regiment, with Dillon in command, was to see extensive service in the numerous wars of Louis XIV: in Spain (1693–7), where Dillon distinguished himself in the capture of Barcelona; in Germany under Marshal Villeroi (1701); and in Italy (1702). It was in Italy that Dillon performed one of his greatest feats, successfully defending Cremona in 1702 when the city was besieged. As a reward for such services he was promoted brigadier (1702) and later maréchal de camp (1705). Continuing to campaign in Italy, he was present at the siege of Mirandola and the battles of Cassano (1705) and Castiglione (1706). Promoted to lieutenant-general in 1706, he commanded the left wing of the French army in the following year, successfully raising the siege of Toulon. In 1709 he served under the duke of Berwick in Dauphiné, decisively defeating the Piedmontese general Rhebinder at the battle of Briançon. Created Count Dillon by Louis XIV in 1711, he was appointed as governor of Toulon. Two years later he commanded the forces besieging Kaiserslautern, forcing the surrender of the town. In 1714 he embarked on his last campaign, serving again with Berwick in Spain where he supervised the siege operations at Barcelona.
Although regarded as a brave and capable general, Dillon received no further military appointments, possibly because of his staunch support for the exiled Stuart monarchy, which after 1715 was often an embarrassment to the French government. His loyalty to the Stuarts was rewarded with the appointment of ambassador to the French court (1717–25) by James III, the ‘Old Pretender’. He was made a commander of the Order of St Louis in February 1717 in recognition of his military and diplomatic services, and in June 1721 was created Earl and Viscount Dillon by James. He retired from active service in 1728, and died 5 February 1733 at Saint-Germain.
He married (1699/1700) Christina Sheldon (1684–1757), maid of honour to Queen Mary Beatrice of Modena, and daughter of Ralph Sheldon, equerry to James II; they had five sons and four daughters. His sons Charles (1701–41), Henry (1705–87), James (d. 1745), and Edward (d.1747) commanded the Regiment of Dillon in succession. Charles and James succeeded as 10th and 11th viscounts Dillon and returned to live in Ireland. A fifth son Arthur Richard Dillon (1721–1806) became archbishop of Narbonne and president of the states of Languedoc, and went to London after the revolution. A grandson Arthur Dillon (1750–94) was governor of Tobago and a general in the French army. The last colonel-proprietor of the Dillon regiment in France, he was guillotined during the Terror. There is a large collection of Dillon letters in the Stuart papers, deposited in the Royal Archives at Windsor Castle, and in the Archive Nationale in Paris.