The Cap of Perseus is an article of clothing found in classical mythology. According to the myth, it had the power to render its wearer invisible. It was given to Perseus by Athena as the goddess's contribution to the hero's quest to slay the Gorgon Medusa.

Cap of Perseus in Thessalonica[]

In the sixth century AD, the Cap of Perseus was in the possession of Perseus' distant descendant, Gorgonius. Gorgonius lent it to George so that the Christian would be able to pass through the Slavic lines undetected when traveling between his home city and his pagan allies in the countryside.

After the siege was broken, George returned the cap to Gorgonius, but not before using its power of invisibility to frighten Menas as punishment for the aristocrat's bad behavior.