Over the centuries, they exploited every pagan event. Yule logs came from the pagan Norse festival. Holly, ivy and mistletoe - fertility symbols - decorated churches. Even the fir trees of Roman Saturnalia were used.
Now Christians have their eyes on Halloween - that Disneyesque, US trick-or-treat import. They say dark forces frighten children and encourage anti-social behaviour. Rather than spoil the fun, a group of educators are promoting alternatives in schools, with parties themed on Noah and Joseph and his coloured coat.
So, paganism gives way to apocalyptic visions of the deluge, a jealous god and four shifty, almost murderous, brothers on the make. Wonderful education.