Premise: Witta son of Wecta is mentioned as a Jutish chieftain in the 449 entry of the "Anglo-Saxon Chronicle" as the father of Wihtgils and the grandfather of Hengest and Horsa. He also appears in the same role in Henry of Huntingdon's "Historia Anglorum". He is most probably mythological, but as a historical person he would have been born around 400 AD.
Hypothesis: Henry of Huntingdon's "Historia Anglorum" was a best seller in 664.