I know most of the history of the area of Raetia (by which I mean the Roman province, today roughly resembling the states Bavaria and Baden-Württemberg) from the first sources we have until today, except for the time from 15 - 550 CE.
This area used to be settled by Celts, but most of them migrated for some reason (Germanic raids?) before the Romans conquered it. I read that most Romans there were Foederati garrison troops.
What I would like to know is, what happened? Did Rome make no attempts to settle this area? If they did, with who? How did the population change after they retreated from the northern Limes? Did all the Romans (including the Romanized Celtic population) retreat?
Basically I would just like to get as much information about this period as we have available to us.
(other similar sources about the Goths, Vindelici, etc.)
Several books about Bavarian history (I forgot the exact titles)