The names applied to Tara's various humps and mounds were adopted from ancient texts, and mythology and religion intertwine with the historical facts. The Protestant church grounds and graveyard spill onto the remains of the Rath of the Synods, a triple-ringed fort where some of St Patrick's early synods (meetings) supposedly took place. Excavations of the enclosure suggest that it was used between AD 200 and 400 for burials, rituals and living quarters. Originally the ring fort would have contained wooden houses surrounded by timber palisades.

Excavations 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.