The sitter is identified in the Cartwright inventory as 'ye Duchiss of Suffouck'. This has been taken to refer to Frances Brandon, Duchess of Suffolk (1517-59), the mother of Lady Jane Grey. However, the costume appears to date from after Frances Brandon's death. Jeffree suggests that she may be Catherine Willoughby de Eresby (1519-80), fourth wife of Charles Brandon, Duke of Suffolk.
