Luca Signorelli - The Archangel Gabriel - Walters 37520

This image of the archangel Gabriel, which has suffered some damage, is most likely a fragment from a much larger painting of the Annunciation, which would have had the Virgin Mary on the right. The white lily held by the archangel is symbolic of Mary's virginity.
The perfectly regular profile, the long curling hair, the gracefulness of the hands, and the overall emphasis on contour lines are characteristic of later 15th-century central Italian painting, of which Signorelli was one of the great masters.