Answer:
Considering the time in which he wrote, which source would probably have provided Bede with the most reliable info that Britain had "twenty-eight noble cities"... Records from a monastic library. You just studied 10 terms!
One unlikely tale that Bede includes in his history is how the Scots told the Picts to go move to Britain. Bede most likely would not know of how the Picts and Scots interacted, or if the Picts would have been truly willing to deal with the Scots saying 'no' and having to sail to Britain.
Explanation:
