For anyone who can use BBC iplayer I can recommend a program on BBC. How the Celts saved the English. Basically its a docu/drama on pre-christian Ireland, time of the Druids and how St Patrick "converted" them to Christianity, thereby bringing reading and writing in Latin to Eire. (Previously a country with only oral history and no exposure to Latin script - therefore "Barbarian and Pagan") Consequently all the monasteries where full of monks who copied out great works of literature and learning into Latin saving them for posterity. After the Romans left England (it was a bit cold and miserable!) the country fell into generations of war with the Germanic celts (anglo-saxons) and middle England hit its first dark ages. Northern/Western England were not conquered and remained celtic. It was with the knowledge provided by the Irish monks that peace and Christianity was restored to middle England.
Despite just being a dramatic account of the story, the presenter does acknowledge that the native Irish didn't really wholly embrace this new Christianity, they just went along with it and built stone churches directly on top of their druidic sacred sites and converted their God/Goddess's names and festival days to nearest catholic saint.
It follows with a few shots of druids reading entrails for divination etc etc and then cuts to modern day Ireland with shots of people visiting ancient groves and leaving offerings to their Gods.
It might be of interest to those of you less familiar with the history of Ireland and England in 4-5th centuries. Just a little light TV not a serious documentary but quite enjoyable.