From the display:

Gorgets, designed to shield the neck, were one of the last vestiges of protective plate armor on the battlefield. While functional gorgets were made with two steel plates (front and back), this is an early example of a single-plate, ornamental version.
Made by a goldsmith from soft brass and then gilded, it would have been worn as a conspicuous symbol of rank. The image of Athena, Greek goddess of war and wisdom, at the center might indicate that it was made for a military engineer or high-ranking officer schooled in the art and science of war.

Through prior acquisition of the George F. Harding Collection;
Laird Landmann Arms and Armor Fund.