The disc, circa 312 to 410AD, found near Swaffham in February, is inscribed ‘Antonius, may you live in God’.
Adrian Marsden, finds officer based at Norwich Castle Museum, said: “We have practically no other evidence for any Christians in Norfolk.”
The disc was declared treasure at an inquest in King’s Lynn.
Mr Marsden added: “The disc that would have been set into the bezel from a signet ring constitutes important evidence for Christianity in late Roman Norfolk.
Story: BBC News | Photo: PAS