Leonard Limousin (attrib) Early large Limoges Enamel and gold on copper, probably Anne d"Este or Catherine of Lorraine circa 16th Century
Léonard Limosin (* around 1505 in Limoges to around 1577) was a French enamel painter and goldsmith .According to dated works, he worked for the French kings Francis I and Henry II from 1532 to 1574 ,
What we found on google...This information comes from a description of a smaller version in the collection of the British Museum: "Painted Limoges enamel plaque; copper; set in an antique carved gold leafed frame; portrait bust of unknown woman, probably Anne d'Este, or Catherine de Lorraine, Duchess of Montmorency"; painted in semi-opaque enamels and translucent enamels over coloured foils.

This is a larger oval variant of the one owned by the British Museum which is a fraction of the size of this piece. The enamel painting is likely 16th century and is secured into the frame with leather that has been shaped and glued into place. The leather is very brittle with age, but is intact.The enamel work is exceptional and the plaque itself measures over two feet in height. Framed it measures 44.5"H x 24"W The frame is carved gold leafed wood and probably dates to the 18th century, but could be earlier.
44.5"H x 24"W

museum piece in nice condition considering its age. some wear, some evidence of possible restoration to background upper left, minor flea bites etc(but the enamel work is secure, no flaking seen)....see photographs attached