Daughter of the third Duke of Abercorn, she was one of those rare women of whom people speak only in superlatives of praise. Not merely was she a great beauty; she was an exceptionally loving and sympathetic person, possessed of what St. Paul describes as "the spirit of wisdom and understanding". If her husband was ingrowing, she was essentially out-going and so filled up what was lacking in him.
She was also highly intelligent. Like most girls of her class and generation, she had received very little formal education. But she set out to educate herself and, so well did she succeed that she could easily hold her own in the company of the scholars and "savants" whom her husband frequently entertained at Althorp.
She had a son and daughter of her own and she acted almost as stepmother, but a very loving and beloved one, to her husband's young sister, Margaret. The relationship between Jack and Cynthia Spencer is in some ways reminiscent of the relationship between George VI and Elizabeth the Queen Mother, to whom Cynthia Spencer acted as Lady of the Bedchamber, thus maintaining the link between the Spencers and the Royal Family.
This beautiful and beloved woman died in 1972 after a long and distressing illness, leaving her husband desolate. 

The Spencers of Althorp, Georgina Battiscombe.

Source: Leo van de Pas