Lady Louisa Magenis appears on the 1861 census, living at Sandleford in Berkshire with her husband, who abbreviated his first name to 'Rd" on the census return. A retired Major in the Army, aged 29, he was a British Subject born in Mauritius. She gave her age as 23 (so she was born about 1838) and her place of birth as Southampton.

According to Hart's Army List for 1863, a Richard Henry Magenis retired with the rank of Major from the 32nd Regiment of Foot on 20 July 1858. According to the International Genealogical Index, Richard Henry Magenis married Louisa Anne Lowry-Corry on 14 June 1860 at Waringstown, County Down, Ireland. Lady Louisa Anne Lowry-Corry was born on 17 November 1837, the daughter of Armar Lowry-Corry, Viscount Corry, later 3rd Earl of Belmore. Her brother, Sir Somerset Richard Lowry-Corry, who succeeded as 4th Earl of Belmore in 1855, was another visitor to Silvy's studio.