An Ancestry study has this to say (slightly reformatted for readability):
This is according to new analysis of the genetic history of two
million people worldwide by Ancestry, the leader in family history and
consumer genomics, based on data collated from the AncestryDNA home
DNA test that examines a person’s entire genome at over 700,000
Do you know what the difference is between an endonym and an exonym?
An exonym or xenonym is an external name for a geographical place, a group of people, an individual person, or a language or dialect1. It is a common name used only outside the place, group, or linguistic community in question. An endonym or autonym is an internal name for a geographical ...
The short answer is we're not sure.
When the Roman State was in decline and had to withdraw from England, (coincidentally?) Germanic tribal power was on the increase. That left a power vacuum in England at the same latitudes that coastal Germanic tribes were already living on the opposite shore of the North Sea. Unfortunately, it also left a literacy vacuum,...