The most important piece of jewelry for men during the Roman Empire (27 B.C.E. –476 C.E. ) was a signet ring, also called a seal ring. Signet rings were first made out of iron but later came to be made more commonly of gold, especially for government officials and honored military men. The center of the signet ring held a stone ornament. The stone, engraved with the wearer's initials and sometimes decorated with a picture, such as the head of the Greek hero Hercules, was used to stamp the wearer's signature in sealing wax to authorize important documents. Although no longer used for signatures, signet rings remain popular pieces of jewelry for men in many Western cultures.
Norris, Herbert. Costume and Fashion: The Evolution of European Dress Through the Earlier Ages. London, England: J. M. Dent and Sons, 1924. Reprint, New York: E. P. Dutton, 1931.