The Historic Ring of Ku-enlila Gromeur is a 2796 years old piece made by Ku-enlila Gromeur, a jeweler living in Istanbul / Constantinople / Byzantium.
Considering its age and the quality of the work, people consider it of the highest value.
It is engraved with central asian patterns and some symbols pertaining to Zoroastrianism.
This piece doesn't exist, but as a legend. It is said that in the year 1618, Epiphaneia Gromeur, the owner, made use of it in Lisbon to empower the Gromeur family. Now it is lost, or broken, we will never know.