We do not know.
My very personal* hunch: since it stresses the heroism of the Geats, as well as their religious ignorance - "they knew not their Maker" in modern translation, and neither did they expect resurrection but burned Beowulf on a pyre like Hektor at the end of the Iliad - it was maybe written to inspire missionaries to go from England to ... nowadays it is The Hising island, Gothenburg, and so on.
Like Pope Gregory who had a dialogue about some slaves he then bought free:
My very personal* hunch: since it stresses the heroism of the Geats, as well as their religious ignorance - "they knew not their Maker" in modern translation, and neither did they expect resurrection but burned Beowulf on a pyre like Hektor at the end of the Iliad - it was maybe written to inspire missionaries to go from England to ... nowadays it is The Hising island, Gothenburg, and so on.
Like Pope Gregory who had a dialogue about some slaves he then bought free:
- Qui sunt?
- Angli.
- Non Angli sed Angeli. Cuius regni sunt?
- Deira.
- De ira Dei ad gratiam Christi vocati sunt. Quid est nomen regi eorum?
- Ælla.
- Alleluia ibi cantabitur.
Now it was the turn of the English to have that charity for Westrogothia and Ostrogothia in what now is called Sweden.
*J R R Tolkien may have agreed. I am not sure I am not repeating some halfforgotten thing.