Let's say I am a German living in a semi-nomadic settlement close to the borders of Rome but far enough so to not be bothered by them throughout my life.
Then for some reason, my relatively small community of about 500 people moves westward with intent to settle.
How would the transition into Roman territory look like? Would the community be killed off? Would they be captured and sold into slavery? Would they even be noticed?
I am aware that the location is relevant here since Romans had forts along strategically important river crossings and such. So if anyone could touch upon the possible outcomes and the conditions required for such outcomes I would be very grateful.
I highly suggest Peter Heather on the Fall of Rome. He touches upon the barbarians moving in and settling within Roman spheres of influences and propagates the idea that it was Roman trade which helped them eventually coalesce into greater tribes with greater centralisation and which therefore posed the very issue and scenario that you described.