Tara's Protestant church grounds and graveyard spill onto the remains of this triple-ringed fort where some of St Patrick's early synods (meetings) supposedly took place. Excavations suggest the enclosure was used between AD 200 and 400 for burials, rituals and dwellings – originally the ring fort would have contained wooden houses surrounded by timber palisades.

Archaeologists have uncovered Roman glass, shards of pottery and seals, showing links with the Roman Empire even though the Romans never extended their power to Ireland.