Originally Posted by
rothaer
I think I can explain.
The place name research by Udolph (1994) strongly suggests that the Germanic migration to Britain was notably simpler than what is commonly taught. Saxons had migrated to England but mainly from the adjacent side of the English Channel. At that time (at abt. 450 AD) they had already lived there for centuries all the way from the Rhine mouth to Aremorica (the mainland part of the so called Litus saxonicus). Also, Flandres is shown as a main source of Germanic migration to England. It's a confusion to suppose Lower Saxony to be the direct source of Saxons migrating to England, though there likely was some migration as well.
Germanic Angles were distributed here and there in Germania, just f. i. they made up an important part of the new emerged Thuringian tribe. It's just Bede's good guess that they came from that small reggion called Anglia in Schleswig-Holstein. He had simply no clue and all people today just follow his (expressly) guess whithout own considerations. His guess might be true, but the Angles in question could as well have been in the Rhine mouth proximity.
Finally the Jutes. This is for sure a misstake to assume any notable migration from Jutland to England. There is absolutely no place name indication for that and also, the Germanic settlers in the areas that were settled by "Jutes", Kent and the Isle of Wight, do show the Germanic settlers with the biggest (!) influence by Romans in their material culture. Out of the three mentioned tribes Juteland-Jutes would, in contrast, be these Germanics with the least contact to Romans. But there was a small Germanic tribe called Eotas that had lived at the Rhine mouth. Maybe these Eotas once, centuries ago, had some connection to Jutland-Jutes, but this would be pure speculation based on the name. Also, it's close to absurd to think that the big Jutland peninsula should have got "emptied" by Jutes migrating to the "micro" territories of Kent and the Isle of Whight. So we can actually better ignore all these big arrows on history maps that fantasizes about the migrations of Jutes from Jutland, Angles from that small Anglia region and Saxons from Lower Saxony to the British Isles.
The mentioned by me Germanics simply crossed the English channel and the connection was the strongest where there was the shortest distance. Still in the 9th century the Pas de Calais was Flemish settled (the inhabitants later became Frenchicised) so you had something like a pretty direct Germanic language contact. Between Kalen (Calais) and Dover you have just 32 kilometers of water. Of course these Germanics that had lived in Northern France for centuries as Germanics had picked up some "France_IA" DNA.
Now, this huge migration coincides with the Frankish advance to the sea. So obviously all that today tribal Lower Franks in Netherlands and Flandres were no Franks or not yet there at that time. So these areas will have been inhabited by Saxons, Eotas and maybe even Angles. Remaining folks were tribally Frankicised and Franks did immigrate to there. Maybe the Saxons were fleeing the Franks, maybe Franks were pulled to advance in that direction after many Saxons had left and maybe it was all together a combination of various push and pull factors, on the mainland and on the British Isles.
