The Church

Officially the Roman Empire was Christian at the start of the 5th century, but there is evidence of rural pagan temples being refurbished at the start of this period in western Prydain. However, most temples seem to have been replaced eventually by Christian churches on the same site or nearby. "Celtic" churches or monasteries seem to have flourished during this period in the British areas, such as that at Caer Witrin (near modern Glastonbury), but the "Saxons" were pagan. This reinforced a great antipathy between the peoples.

In 429, a British Deacon Palladius had requested support from the Pope in Rome to combat Pelagianism. Bishops Germanus and Lupus of Troyes were sent. Germanus, a former military commander, is reported to have led the British to the "Hallelujah" victory, possibly in Wales. Germanus is said to have made a second visit to England later. Participation by a British bishop at a synod in Gaul demonstrates that at least some British churches were in full administrative and doctrinal touch with Gaul as late as 455.

All of the major cities of Prydain are openly Christian, with varying degrees of suppression or tolerance toward "pagan" beliefs depending upon how far away they are from Rome. Londinium, for example, is completely Catholic and extremely intolerant of anything not official Church doctrine while a northern city like Din Eidyn are generally more pagan than Christian.