Each had its own King and Pope Gregory wanted Augustine to visit the Anglo-Saxons and persuade them to abandon their Pagan beliefs and embrace the Christian way of life.
Religion played an important role in politics, and as the legend goes, in 987, the Rus prince Vladamir I decided it was time to abandon Slavic paganism, and sent emissaries to explore neighboring faiths.
As Christianity rose in popularity, the Norse religion struggled to maintain itself against a religion that was so very different, and once Christianity triumphed over the pagan Norse beliefs, the temples were destroyed.