What form (or forms) of paganism were practiced in the time that Beowulf was SET in (not written down in)?

I am currently trying to show the different religious takes on Beowulf, starting with the actual pagan religion, polytheism, or mythology (however you would like to term it), and then speaking of the Christian influences found in translations and mcripts from 1000 A.D. to present, and then I am also comparing religion in the film versions. I am just having trouble finding out exactly what religions were practiced, and I'm also having trouble finding out how many times (and when) Beowulf was re-written. The version in our text, is I believe from the Cotton Mcript (and I'm pretty sure it's the translation by Seamus Heaney), and as far as the setting, there is an introduction in our book that explains the only character that can be historically placed (which I think is Hygelac, but I may be mistaken) was said to live around 520 A.D. so if this is the right character, (who was Beowulf uncle I believe) then that would set Beowulf in the mid 6th century, however I was under the impression that it was Celtic mythology. I am worried however, that given the fact that most people in this time were all trying to conquer one another and impose their religious beliefs, that there may have been other influences as well as or other than Celtic mythology. I know that the geographic setting is in England and Scandinavia, but I'm not much of a history buff, and I am worried about presenting an argument with glaring inaccuracies.