Probably Mary Ann Mieville, daughter of John Louis Mieville. She married Augustus Sillem at St James's, Paddington, on 28 June 1854.

At the time of the 1861 census, the couple were living at Lawrie Park, Summerfield, near Beckenham in Kent, with their children, Louis Augustus, aged 5; Louisa, aged 4; Herman Walker, aged 2; and Stewart Augustus, one month old. Also present on the night of the census were 6 live-in servants. Mrs Sillem gave her age as 30, so she was born in or about 1831. Her place of birth was Marylebone, Middlesex.

Her unusual maiden-name is of Swiss origin, and is a locational surname from a place called 'Mieville' in the French speaking canton of Vaud, Switzerland, near Lausanne.