Saxon where heathens till Karl der Grosse (/Charlemagne) destroyed their cult places and made them christians by sword. Guess was 772.@Bardowick:
EDIT: Correction, a church is of course not present att he start of the mod, as it was pagan at this timepoint, afaik, but i'm not sure about that, if the Romans had a christian impact in the 4th century in this area.
What's with Haithabu? Already considered?
http://de.wikipedia.org/wiki/Irminsul
http://de.wikipedia.org/wiki/Eresburg
@Heiðabýr
http://en.wikipedia.org/wiki/Hedeby
Anyway, great to read you found some other places maybe important for later (Viking) times too. I will have to check them for our mod times (starts 840 AC).
Keep up the good work!