Henrietta Harley, Countess of Oxford and Countess Mortimer

Henrietta Harley, aged 24, by Godfrey Kneller

Henrietta Harley, Countess of Oxford and Mortimer, née Henrietta Cavendish Holles, (11 February 1694-9 December 1755) was an English noblewoman, the only child and heir of John (Holles), the 1st Duke of Newcastle and his wife, the former Lady Margaret Cavendish, daughter of Henry (Cavendish), the 2nd Duke of Newcastle-upon-Tyne.

Her hand was sought in marriage even in her youth, as a means of alliance with her powerful father, by the Intendant of the Court of a Count of the Holy Roman Empire in December 1703, the Elector of Hanover's son in June 1706, the Duke of Somerset's son Lord Hertford in 1707-11, Count Nassau in 1709, and finally Lord Danby (grandson of Thomas Osborne, 1st Duke of Leeds) in 1711, before her father settled on the son of the 1st Earl of Oxford. She thus married Edward Harley (later the 2nd Earl), on 31 August 1713, at Wimpole. They had two children. Their son, Henry Cavendish Harley, lived only four days. Their only child to attain maturity was Margaret (1715-1785), and so whilst Margaret inherited most of the combined Holles-Harley fortunes on her parents' deaths, the title of Earl of Oxford passed to Edward's cousin (also Edward).

John Dryden wrote of Henrietta:

"No single virtue we could most commend.

Whether the wife, the mother, or the friend;

For she was each in that supreme degree,

That, as no one prevail'd, so all was she."

Sources

• http://www.nottshistory.org.uk/articles/tts/tts1923/oxford/oxford1.htm