Lord Tony's Wife, an Adventure of the Scarlet Pimpernel

Popular novel, first published in 1917. According to Wikipedia: "Baroness Emma Magdolna Rozália Mária Jozefa Borbála "Emmuska" Orczy de Orczi (23 September 1865 – 12 November 1947) was a British novelist, playwright and artist of Hungarian noble origin. She was most notable for her series of novels featuring the Scarlet Pimpernel. Some of her paintings were exhibited at the Royal Academy in London.