Susan Buchan, née Grosvenor, was born in London, England, a daughter of The Hon. Norman de L'Aigle Grosvenor and his wife Caroline Susan Theodora Stuart-Wortley, and was a cousin of the Dukes of Westminster. In 1907, she married John Buchan, a novelist and politician, with whom she had four children. She became Baroness Tweedsmuir when he was created 1st Baron Tweedsmuir in 1935 and appointed Governor General of Canada. She wrote more than a dozen books and plays, including biographies of Lord Wellington and a memoir of her husband.