“The Book of Kells” is an illuminated manuscript of the Gospels. It’s a thoroughly Christian book (it is the Gospels, after all!).
But that doesn’t seem to matter to Tomm Moore, who made a fanciful cartoon last year, called The Secret of Kells. Moore has apparently ripped the book from its Christian reality and turned it into a magical text, and created a story of fairies (though set in the context of a monastery preparing for a Viking attack).
I’d never heard of it–probably you haven’t either. But it’s one of five animated feature films nominated for an Academy Award. So that lifts it to great prominence. And those on the New Age circuit, who imagine Celtic spirituality to be pagan, will soak up his pagan fantasy.