Carnelian intaglio ca first century A.D. in later mount.
The mildly domed intaglio is depicting three mounted riders.It has been suggested to me /with thanks to SW / that the gem’s carving is of Castor and Pollux.In Greek and Roman mythology, Castor and Pollux were twin brothers, together known as the Dioskouri. Their mother was Leda, but Castor was the mortal son of Tyndareus, the king of Sparta, and Pollux the divine son of Zeus, who seduced Leda in the guise of a swan. Though accounts of their birth are varied, they are sometimes said to have been born from an egg, along with their twin sisters Helen of Troy and Clytemnestra.
In Latin the twins are also known as the Gemini. When Castor was killed, Pollux asked Zeus to let him share his own immortality with his twin to keep them together, and they were transformed into the constellation Gemini. The pair was regarded as the patrons of sailors, to whom they appeared as St. Elmo’s fire, and were also associated with horsemanship.Since the riders have no helmets and apparently Castor and Pollux are normally depicted with helmets the image could be the representation of Odysseus and Diomedes. Odysseus aided Diomedes during the successful night operations in order to kill Rhesus, because it had been foretold that if his horses drank from the Scamander River, Troy could not be taken.
Interestingly the riders are not armed. Could be depicting a historical event..?The shape of the gem ,being “cushion” shaped is also quite unusual.
The modern mount is 18 ct yellow gold.
Size of bezel: 23 x 17 mm
Ring size: “R” + 1/2 = US 9