The Standard Theorem of Beletum Benouz is a 2811 years old piece made by Beletum Benouz, a mathematician living in Istanbul / Constantinople / Byzantium.
Considering its age and the quality of the work, people consider it of high value.
It is engraved with central asian patterns and some symbols pertaining to Ancient Mesopotamian religion.
This piece doesn't exist, but as a legend. It is said that in the year -386, Fabia Benouz, the owner, made use of it in Prague to empower the Benouz family. Now it is lost, or broken, we will never know.