We see this often: "Well, the Egyptians already had the idea of a dying and resurrected God way before the Christians did!"
But Father Dwight Longenecker, discussing Tom Bombadil, quotes C. S. Lewis debunking this silly idea:
Pagan wisdom is a foreshadowing of the Christian gospel. 'If paganism could be shown to have something in common with Christianity, "so much the better for paganism," not "so much the worse for Christianity."'Read his whole essay, which is quite good.