I do believe this is a 19th century painting of an 18th century woman, such as is the case with many done in early to mid-1800s for souvenirs of Grand Tour travelers. They loved the paintings they saw. They loved the historical figures they learned about and the architecture, and they loved souvenirs. One such traveler might have bought this from a street vendor outside Versailles, as it's of a woman from the Louis XVI and Marie-Antoinette era of fashion and look. It's a nice quality for these, and I suppose there is a chance it's authentic 18th century, but my experience as a longtime collector pegs it as souvenir, c.1830-50s, those early Victorian travelers' memento. And I'll price it as that. Full measurements noted on the photos.
Very good to excellent for age and type, even having been a souvenir of almost a century after women who dressed like this actually lived, it's a fine little antique of 150 or more years. Beautifully preserved, the convex cover glass is fully intact and has done its job very well. No flaws to the old painting. A bit of age and imperfection to the wooden part of the frame, and a brass mat. I did not open this one up since it's sealed from the back and the cover glass has remained mostly very clean inside, so photos have been taken through that thick convex glass. She's really a lovely portrait with her face just 1/2" from chin to her hat rim.
