In an ebonised wood frame with gilt brass decoration and hardstone inserts, 13cm by 18cm.
The portrait is attributed to Leonard Limousin (active 1532-1575), a prolific enamellist, most notably at the Courts of Francis I and Henri II of France. He also enjoyed a reputation as an oil painter.
Claude de Lorraine (1496-1550), a powerful French aristocrat who was educated at the Court of Francis I, became the 1st Duc de Guise in 1528.
He was the grandfather of Mary, Queen of Scots.