A group of drawings of the same type as the present ones are in the Louvre, J. Guiffrey and P. Marcel, Inventaire général des dessins du Musée du Louvre et du Musée de Versailles, Paris, 1933, I, nos. 219-25, illustrated. A further three drawings from the same series were sold at Christie's, London, 23 March 1982, lot 102, illustrated. They all show frontal or profile portraits of Kings, all with brown ink framing lines heightened with gold, and the name inscribed under the portrait. The Kings represented date from the Middle Ages to the late 16th Century and are mostly French. The artist probably undertook a series of royal portraits which were intended to be bound in book form