St. Peblig’s Church, or in Welsh, Llanbeblig, is located in Caernarfon in Gwynedd. It is one of the oldest churches in Wales and certainly one of the oldest religious sites.

St. Peblig’s is currently adjacent to visible remains of the Roman fort of Segontium. Founded in 433, the church was was built over the top of Roman ruins, including a temple to Mithras, and its graveyard contains graves of Roman soldiers. Peblig is the Welsh name for Publicius, whose father was Magnus Maximus, known in Wales as Macsen Wledig and the ruler of the western Roman empire starting in 383 AD. Peblig’s mother was the daughter of a Welsh chieftain, whom according to legend Macsen saw in a dream while in Rome and eventually came to North Wales, only to find her father ruling from the remains of the Roman fort.

The graveyard is extensive, much of which is overgrown and no longer cared for. Roman ruins have been uncovered to the west and to the south, across the road, which include baths, barracks, and commander’s house. The church itself was granted to Aberconwy Abbey during the reign of Llywelyn ap Gruffydd, the last Prince of Wales, and much of what is visible today is from the 14th century.

St. Peblig’s plays a significant role in the first of my Welsh Guard Mysteries, Crouchback.