I'm newly fascinated by the tumultuous period between the Anglo-Saxon invasion/settlement and the Battle of Hastings. What remains by way of primary sources from that time?
You'd probably like the Anglo-Saxon chronicle, which contains entries from the 9th-11th Century.
There's some other British annals as well - there's a short list on Wikipedia (mods, I hope this is okay as a source?).
Life of King Alfred by Thomas Asser. Asser was a welsh monk in Alfred's court who was commissioned to write this biography.
invasions*
There are some good examples at the Fordham source book here http://legacy.fordham.edu/Halsall/sbook1n.asp#Anglo-Saxon%20Britain