Answer:
This is actually an area of intense interest and study for me, and has been for some time. Norse and Celtic myths and legends meet and mingle during a special time in the history of the Anglo-Saxons. Beowulf, the Arthurian legends, the Anglo-Saxon Futhork, all blend elements of both. It is an example of what we call "syncretism" when various religious beliefs and traditions co-mingle along with their parent cultures to create a new form of belief and practice. This "syncratism" of Celtic and Norse traditions is reflected in Beowulf.