This Late Byzantine chalice is set on a metal foot with Greek monograms and belonged to Manuel Kantakouzenos Palaiologos, the Despot of Mystra (1349-1380). The chalice stands out for its jasper cup, cut from one piece of stone, and its dragon handles, which may betray a Venetian influence. The chalice is today part of the treasury at Vatopedi Monastery on Mt Athos.
source: Berliner Byzantinistik/ Berlin Byzantine Studies - FU Berli