(Larry Hurtado) Recent archaeological work at the Roman site, Vinovia (now known as Binchester, in County Durham (UK) has yielded results include evidence of Christianity. In particular, findings include a silver ring with an intaglio inset with an anchor and two fish set in a fashion familiar in early Christian art/symbols:
It is interesting to find this sort of evidence in the remains of a military garrison. The ring is likely from the 4th century CE. For more information on the site and the archaeological work, see here.