Redbad (2018) online

700 AD. Northern Europe is divided into two worlds: the Frisians, Saxons and Danes live above the rivers, below the rivers live the Franks. They want to achieve what even the Romans did not succeed: conquer all of Europe. They put in a new weapon to enslave the Gentiles: Christianity. They target Europe's main trading center, where the Frisian king Aldigisl rules