True, but many things can still trace their way back to before Christianity - for example, the legend of St Nicholas in the Netherlands and in Flanders has him riding a horse over rooftops, which is thought have been derived from Odin's riding through the sky on a horse. He also has assistants, the Zwarte Pietin (Black Peters), which are thought of as remnants of the legend of the ravens that accompanied Wodan.

Nicholas may have been a real person who gave out gives through the goodness of his heart, but modern Christmas has pre-Christian ideas to thank for it's current state.