The presence of any kind of ‘formal’ religion in the European Iron Age is debatable but, as the period progressed, persistent patterns of religious expression began to emerge over wide areas of non-Mediterranean Europe. By the time of Roman intervention, religion began to become codified and personified, and the local deities named in written text and inscriptions, attest to a formalization of cults and gods. Some deities apparently had influence over vast regions, whereas others belonged to a single place. Other topics considered in the chapter are the role of the Druids in orchestrating religion, power, and justice in the late pre-Roman Iron Age, the reinvention of Druidism in Gaul in the Roman period, and the lack of a clear-cut interface when the monotheistic new faith of Christianity was added to the melting pot of established cults in the fourth century AD.