After the collapse of the Western Roman Empire, tribal kingdoms were again established over much of Europe in the wake of the Migration period but they quickly turned into nobility-based feudalism afterwards. By the High Middle Ages, these had again coalesced into super-regional monarchies. Tribal societies remained prevalent in much of the New World. Exceptions to tribal societies outside of Europe and Asia were Paleolithic or Mesolithic band societies in Oceania and in parts of Sub-Saharan Africa. Europeans forced centralized governments onto these societies during colonialism, but in some instances tribes have retained or regained partial self-government and their lifestyles.