Roy Precious - Antiques & Fine Art has dated this piece to the Before 1700 period.

Mary Stuart would have been 32 years old at that time and that looks about right for the sitter.
Image 5 shows an image of Mary as Queen Dauphiness of France by Francois Clouet at the age of sixteen and there does seem to be a resemblance between the young girl and the mature woman.

It is possible that the portrait was painted in the early 17th century when James Stuart, Mary's son, was on the Scottish and English thrones and Mary's image was revamped from traitor to martyr.
Of course, it may also be that the sitter was a noblewoman who looked like Mary. There are so many images claimed to be of her and so many artists depicted her in their own way...half the portraits seem to bear no resemblance to each other, especially the 18th and 19th century ones.

This portrait came from the old collection of an ancient and noble Scottish family and was in that collection for almost 100 years. Verso a manuscript pen and ink label is inscribed " Mary Queen of Scots by Mark Garrard" (Marcus Gheeraerts)

Regardless of the identity of the sitter this remains a beautiful and highly skilled portrait of an attractive and very wealthy noble lady.
FRANCOIS CLOUET (c. 1510 – 22 December 1572), son of Jean Clouet, was a French Renaissance miniaturist and painter, particularly known for his detailed portraits of the French ruling family. His work is remarkable for the elaborate finish of all the details, the extreme accuracy of the drawing, and the exquisite completeness of the whole portrait.
SIZE: Panel 18.5 x 13.75 inches.
Framed size: 26 x 21.5 inches.
PROVENANCE: Old collection of an ancient and noble Scottish family.
Roy Precious - Antiques & Fine Art has dated this piece to the Before 1700 period.
Roy and nadine precious: specialists in portraiture from the 16th to the 20th century. Established in 1972.
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