The old Celtic and Saxon polytheistic beliefs were really deeply ingrained, and people were unsure about this new belief structure. I should imagine that many received the 'good news' with the sort of scepticism that most of us would reserve for the dogma of Scientology.
The Romans had had a couple of experiments with the calendar, more, I believe, in a drive for accuracy and efficiency than for any hard and fast religious reasons, but the devotees of the old Celtic and Saxon religions measured their days by the passage of the sun, moon and seasons.
The problem for the church being that whilst many may have converted, probably just for five minute's peace, (they were most likely fed up with the spineless insipid missionaries knocking on the door of the hovel, quoting selected lines of Latin at them to prove some point which didn't really make sense to them anyway, and leaving parchments explaining how believing in this Jesus chap would explain the horrible stuff that was going on in the village and give them some comfort, which they couldn't read.), when the big important stuff happened, they reverted to the old ways.
Rollo (not the kid's TV character boy-king, but the ancestor of William the Bastard Conqueror) was given the province of Normandy, he was given it on two conditions; firstly that he'd stop sending raiding parties into France, as it was getting on everyone's tits, and secondly that he converted to Christianity as it was what all the cool, progressive, cutting edge 10th Century European leaders were doing. Come his death, somewhere in the late 920's, he displayed a superb capacity for pragmatic cynicism by having a hundred Christian devotees beheaded in front of him in his death bed, to appease the old Norse gods he had followed. Then, just to make sure, he made sure that the Christian organisations were given a shit load of gold, to appease them for the fact that he'd just offed a hundred or so of their mates.
Of course, the general population didn't really have the contacts and resources to slaughter a load of people and then give out a ton of cash in recompense, but when the landmarks of the year rolled around they'd still adhere to the old ways.
So when the shortest day came around, when the Sun reached its lowest point in the sky, they'd have a little celebration to mark the fact that the days would now start to get longer. But there was no room in the church calendar for this sort of stuff, it had to be changed. But how to do it? Well, of course, that was when Christ was born. (As an aside I saw a programme on one of the satelite channels a while back in which a historian was saying that the Roman census was carried out in the summer, so there would have been no race to Bethlehem in December.) So, you can have your little celebration, we'll just come in and change the reason for it.
Similarly when Spring rolls around, and everyone's thoughts turn to eggs, bunnies and little fluffy chicks, it has nothing to do with nature coming out of hibernation, it's all to do with the death and then, then, (this is the good bit), the re-birth of Christ. At the same time of year? What are the chances? You've got to hand it to the church, it's a great bit of marketing.
So when the Bishop of Arundel and Brighton gets involved in a story like this:
A bishop has urged parents not to let their children dress up in ghoulish gear in the run up to Halloween.The Rt Rev Kieran Conry, the Bishop of Arundel and Brighton, wants to reclaim the festival as a Christian celebration.
He suggested children should dress up as saints rather than traditional Halloween garb.
In the Christian calendar, Halloween falls on the day before All Hallows' Day, a day to honour all the saints.
The Rt Rev Conry said Halloween had "no meaning to it whatsoever" and was a waste of money for parents.
He's completely forgetting that people have been marking the point in the year when the trees lose their leaves and the plants die back, or at least stop growing, for thousands of years. This is why people dress up as ghosts and skeletons, it is a marker of death in the natural cycle. And what does it say about us that 1400 years after death of Augustine that when the big markers roll around, we still go back to the old ways to recognise the landmarks?
Perhaps that marketing campaign by the church, almost one and a half thousand years in the running, hasn't been as effective as they thought, because they are still fighting to stop people celebrating in ways that we've done since before the Roman conquest. Of course, the difference now is that the church can't have us shunned, fined, imprisoned or put to death for failing to conduct ourselves in a manner which they find acceptable.
No, it would appear that that particular little perk has now passed to the adherents of the green church and the anti-smoking/drinking/eating church. Nature abhors a vacuum, and it looks like Rome and Canterbury's loss is their gain.