She was the eldest child of Baynes Wright Smurthwaite by his wife Charlotte Lilias Stirling. Her given name was Dorothy, but after her parents divorced she changed it to Mary Duff and kept her mother's maiden name of Stirling as her own.
On 4 January 1914 her engagement to John Churchill Craigie, son of Pearl Richards Craigie, was announced, but her first marriage was to Edward Luttrell Grimston Byrom, son of Edward Byrom DL of Culver, Devon and Kersal Cell, Lancashire, who served as High Sheriff of Devon in 1888, by his wife Florence Maria, daughter and co-heiress of Marmaduke Jerard Grimston, of Grimston Garth and Kilnwick. Luttrell Byrom petitioned for divorce in 1915 citing one G. Henderson as a co-respondent. Her second marriage was at Edinburgh on 26 January 1917, to Sir Roger Thomas Twysden, a naval officer. He had succeeded as tenth Baronet on 1 May 1911, so Duff became known as Lady Twysden. Their son Anthony, later eleventh Baronet, was born on 11 March 1918.
Sir Roger and Lady Twysden were divorced in 1926. Duff Twysden eventually married artist Clinton King. Mary Duff, Lady Twysden died in Santa Fe, New Mexico of tuberculosis when she was forty-five.
- Darryl Lundy, thepeerage.com
- M. C. Rintoul, Dictionary of Real People and Places in Fiction, Routledge, p909 (online at google books)
- Descendants of Walter Stirling, 1567-1656
- online bio
- New York Times report
- Marquis of Ruvigny and Raineval, The Plantagenet Roll of the Blood Royal, Mortimer-Percy Volume, page 193 (online at google books)
- Catalogue of the National Archives
- Tim Powys-Lybbe family database
- Leigh Rayment's Baronetage Page
- Hemingway at the Internet Movie Database