What is "contorniate"

Contorniate \Con*tor"ni*ate\, ||Contorniate \Con*tor"ni*a`te\, n., [It. contorniato, p. pr. of contorniare to make a circuit or outline, fr. contorno circuit, outline. See Contour.] (Numis.) A species of medal or medallion of bronze, having a deep furrow on the contour or edge; -- supposed to have been struck in the days of Constantine and his successors.
--R. S. Poole.

n. A bronze medal or medallion with a deep furrow on the contour or edge, supposed to have been struck in the days of Constantine and his successors.

A contorniate, or contourniate, is a species of medal or medallion of bronze, having a deep furrow on the contour or edge, as if the object had been turned in the lathe. Contourniate medallions were struck in the days of Constantine and his successors. These medals were not struck to be a form of money, but are believed to have been given as gifts, and show the portrait of a variety of earlier emperors.

All that remain of these types of medals seem to have been made about the same time. Jean Hardouin conjectured them to have been struck around the 13th century; other antiquaries go back centuries earlier.

The manner of the work seems to have had its origin in Ancient Greece, and to have been appropriated to honor the memories of great men, principally those who had borne away the prize at solemn games. Such are those remaining of Homer, Solon, Euclid, Pythagoras, Socrates, Apollonius Tyaneus, and several athletae, whose victories are expressed by palms and chariots, either bigae or quadrigae.

The standard catalog of these medals is by Andreas and Elisabeth Alfoldi, Kontorniat-Medaillons, ISBN 3110034840 (v. 1) and 3110119056 (v.2).