" Strangely, Asgard also contained temples, cult buildings where the gods themselves made offerings—but to what or whom? The mythology of the Vikings is one of only a tiny handful in all world cultures in which the divinities also practised religion. It suggests something behind and beyond them, older and opaque, and not necessarily ‘Indo-European’ at all. There is no indication that the people of the Viking Age knew what it was any more than we do. "

― Neil Price , The Children of Ash and Elm: A History of the Vikings