Born in Brampford Speke, near Exeter in Devon, the only daughter of Commander John Viney-Evans and his cousin Eleanor Scrope-Viney (later Mrs Eleanor Yate). In 1815 at Clifton, Bristol Mary married Wyndham Lewis, MP (1780–1838), a colleague of Benjamin Disraeli. In August 1839, the year following Lewis’s death, she married Disraeli at St George’s, Hanover Square in London. Her fortune allowed him to purchase the estate of Hughenden in Buckinghamshire and to live in the style of an English gentleman.

In recognition of Disraeli’s services to the nation, Queen Victoria desired to ennoble him at the end of his first ministry. However, as he wished to remain in the House of Commons, his wife accepted the title in his place and was created Viscountess Beaconsfield, of Beaconsfield in the County of Buckingham, on 30 November 1868. (After Mary’s death, Disraeli accepted the title of Earl of Beaconsfield.)