Princess and foundress, the daughter of Prince Svyatoslav. At the age of twelve she became a nun and then a recluse. Gifted, she copied manuscripts to raise money for the poor. Euphrosyne also founded a convent at Settse. She went to the Holy Land and died in Jerusalem, Israel.
From Catholic.Org
The Cross of St. Euphrosyne or Cross of Euphrosyne of Polotsk, Belarus
Original missing since WWII.