Inscribed 'MARIA . DE . LORRAINE . PAR LA / GRACE . DE DIEV ROYNE DES . COSSE / FILLE . DE CLAVDE DVC . DE . GVISSE.', decorated with the arms of Lorraine, under a royal crown and dated 1611.

The costume of this portrait appears to date from the 1550s and may be compared with Mor's portrait of Mary I of England (RCIN 404442). The inscription identifies the sitter as Mary's exact contemporary on the Scottish throne, Mary of Guise, who married James V in 1538. After her husband's death in 1542, Mary ruled as Regent until her death. She was the mother of Mary Queen of Scots.

The identification of the sitter is based upon the inscription, which was presumably added at the same time as the date (1611), some half-century after the sitter's death. It is therefore unreliable but not impossible. The sitter's features are not incompatible with those of better-documented images of Mary of Guise. It is possible that this portrait was painted in 1611 and based on an earlier image.