Nathaniel Thach's family originated from Suffolk, but settled in the parish of St Martin-in-the-Fields, London. Thach's uncle, John Cradock, father of the artist Mary Beale, was an amateur miniaturist and left to Thach all his prepared vellum rounds in a will dated 1644, in which Thach was already described as 'late of London'. Thach appears to have spent his working career abroad, presumably at The Hague, as all but one of his surviving miniatures represent members of the family and circle of the exiled King and Queen of Bohemia. The Royal Collection holds a group of twelve such miniatures, most of which are copies of existing portraits and can be dated to c. 1650. The present miniature has been identified as Louisa Hollandina, Princess Palatine, second daughter of Frederick V and Elizabeth, Queen of Bohemia and is based on a portrait at Ashdown House (National Trust); another copy attributed to Thach is in the Musée Carnavalet, Paris. Louisa Hollandina, Princess Palatine, converted to Catholicism and became Abbess of Maubisson, near Pontoise. She was an amateur artist and pupil of Gerrit van Honthorst, who worked extensively for the King and Queen of Bohemia. Signed indistinctly on the left: 'NTh' (the NT forming a monogram).