[koheripbal]

In many of those cases the settled peoples they coexisted with are the settled descendents of those same nomadic raiders. That shared ethnicity, language, trade, and intermarriage is what protected them.

The nation of Turkey is a strong historically recent and well documented example of that, with Turkic tribes displacing Kurds, Armenians, and Greeks, not coexisting with them (long term). In short periods, of course there were some cases of peaceful coexistence, but power politics always finds a way to capitalize on ethnic divisions through violence.

Bulgaria and Hungary are much earlier era examples (still visible in genetic testing) . The displaced Slavic and Germanic tribes refugee crisis brought upon various Roman crises in multiple waves, ultimately driving the collapse of the Western Roman Empire.