But also in Medieval times and many centuries before. E.g when Sweden gained control over Scania (Southern tip of today's Sweden) from Denmark in the 17th century they relocated a lot of native Swedes into that area to pacify the population. (I may need to reference this, I am only remembering school history classes...)

All to establish control, though we see it sometimes does quite the opposite. Though I would also think some of it is natural migration. So not always forced, but probably "encouraged".

Though always more when borders have changed. Not to combat an internal "culture"/crime problem.