During the Roman Empire Christianity was persecuted until the early 4th century AD, with the Great Persecution lasting between 303 and 311 AD. With the Edict of Milan in 313 AD, emperors Constantine and Licinius granted liberty of cult for all religions, including Christianity. However, it was only in 380 AD, with emperor Theodosius, that Christianity became the only official religion of the Empire. Crosses of this type would have been worn in everyday life but also buried with the deceased to seek salvation in the afterlife.
To discover more about Byzantine jewellery, please visit our relevant blog post: The Byzantine Empire: Art and Christianity.