Such a cross, also known as an enkolpion, could have been worn as a pectoral cross, which, during the Middle Ages, was an attribute of bishops. Throughout the centuries a great number of crosses were made to hold a secondary relic in them containing pieces of saints’ clothing, pieces of the True Cross, hair fragments, and so on. Crosses offered protection to the wearer and would have been available all over the Byzantine Empire.
To learn more about Byzantine crosses, please visit our relevant blog post: Enkolpion Crosses in the Byzantine Empire.