Aelfwine-

Two excellent hard-copy sources are Henry Mayr-Harting's _The Comingo of Christianity to Anglo-Saxon England_ and Paul Cavill's _Anglo-Saxon Christianity_.

The timing is difficult to pin down because, I think, there is no one moment which can be said to be the beginning of the Christianizing of Britain. Rather there are multiple beginnings, in various locations. 597 is "official" only because of Pope Gregory's famous mission charter to the Angles with the resulting efforts of Augustine and Paulinus.

There is, of course, the legend of Joseph of Arimathea and the origins of the church at Glastonbury. If there is any truth in the stories of the tin-trader that puts Christianity on English soil before the close of the first century (even if he never brought either the teenaged Jesus or the Holy Grail with him).

Meanwhile you have a substantial Roman occupation force scattered across most of Britain from 43 to 410. Many of the rank and file were Christians (St. Alban is the best-known), and when Rome stopped paying their wages many of them married local girls and stayed on, so that would create an "indigenous" Christian population, although absent any trained clergy there would tend to be a blending of Christian doctrine and practice with those of the native religions. Pelagius himself was most likely born in Britain, mid-fourth century. St. Patrick was, of course, the son of Roman parents stationed near what is now Glasgow, born toward the end of the Roman occupation.

In the mid fifth century you have Celestine sending St. Germaine to Britain to dispute the Semi-Pelagians. That's an "official" presence just 150 years before Augustine. 6 generations is not an extraordinarily long time for religious traditions to be passed on. (I put more stock in the likelihood of an ongoing Romano-British church than most historians, but I'm contrary that way . . .)

Meanwhile, on the edges of Anglecynn, there's a pretty steady commerce back and forth between the northern part of the island (Scotland) and Ireland, and Ireland had a vigorous missionary presence both on the continent and in Britain. Sts. Columb in the sixth century and Aidan in the seventh are only the best-known of the missionaries, there were probably many others, some no doubt unknown to history. Welsh Christianity had some influence in Wessex after the revival associated with St. David (mid sixth century). At the same time there was active trade with Gaul and a well-established Gallic Church which would have been familiar to those involved in cross-channel travel. So the fact that the 597 Gregorian mission found, for example, that King Edwin's wife Ethelburga was a Christian is not particularly mysterious (her mother Bertha was a Frankish princess and a Christian).

Which is not to suggest that those early Roman and Celtic missionaries didn't face some serious opposition when they started preaching to the Anglo-saxons!

-Marsaili