I had no idea the use of the maypole was quite so widespread - I thought it was a particularly English thing. I've never encountered any reference to them here in Scotland.
But while we're talking about stealing things, I think this went in several directions, with lots of Norse views and figures being influenced by other religions, including Christianity. Vikings and their sagas aren't exactly ancient.
http://www.orkneyjar.com/history/maeshowe/maeshrunes.htm
[At almost 5000 years old Maeshowe definitely qualifies as ancient.]