The Battle of Ellandun is fought between Egbert of Wessex and Beornwulf of Mercia in September 825.
It effectively ends Mercian supremacy over the southern kingdoms of Anglo-Saxon England and establishing West Saxon dominance in southern England.
"We cannot be certain of being right about the future; but we can be almost certain of being wrong about the future, if we are wrong about the past."
—G. K. Chesterton, What I Saw in America (1922)