Did the European pagan druids actually die off or did they make it too the Lost continents over the Ice Wall and still practicing their paganism over there? I know in official history it was said that most Druids would take a boat to some unknown island and live there among other druids.
Paganism was consumed by Christianity; they converted or their enclaves died off.
Just as Christianity supplanted Rome's paganism, so too did it with the others.
When the UK was overthrown by the Saxons and Normans, they to eventually converted from their Nordic faith to Christianity and melted into the civilisation.
Also, I'd really love it if your crazy flat earth shit were real because it would be cool as fuck, but it's just not at all.