In 1765, Onslow, known for his conviviality, was a founder of the Navy Society dining club. On 18 January 1766, he was appointed to command the
frigate Aquilon in the
Mediterranean, which he did until 1769, and from 12 October 1770, commanded the
Diana in the
West Indies. Admiral
Rodney gave him command of
Achilles on 18 January 1773, in which he returned to England, where he acquired an estate and married Anne, daughter of Commodore Matthew Michell of Chitterne, Wiltshire. They had five sons and four daughters: • Fanny Onslow (1775–1844), married V-Adm.
Sir Hyde Parker (1739–1807) in 1800 and had two daughters and one son • George Cranley Onslow (died in infancy) • Roger Onslow (died in infancy) • Matthew Richard Onslow (1781–1808), married Sarah Seton in 1805 and had two daughters • Anne Onslow (1783–1853), married
Francis Lake, 2nd Viscount Lake (1772–1836) in 1833; married Henry Gritton in 1837 •
Sir Henry Onslow, 2nd Baronet (1784–1853), married Caroline Bond and had four daughters and five sons • Elizabeth Onslow (1788–1861), married Robert Lewis (1793–1840) and had five daughters and two sons • Harriet Onslow (1791–1860), married James Norman Creighton (1786–1838) and had two daughters and one son • Capt.
John James Onslow (1796–1856), married Lavinia Dinning (1796–1871) and had four sons and two daughters Onslow's widow, Dame Anne, died of influenza at Grand Parade, Brighton, on 31 January 1837 aged 85 year. She was buried with her granddaughter at St Nicholas church northern burial ground, Brighton. A note found after her death and addressed to her son, Sir Henry Onslow, contained the following message: "When I am no more, I hope I am going to a world of comfort after all the sorrows I have experienced in this." ==References==