Mistrust of strangers

In the earliest times, prior to the emergence of political society, all those with whom a person was not connected by ties of blood was considered an enemy. All such people, alien to the family or tribe, could be pursued with legitimate hatred as lawful prey to be plundered or slain. In classical times, foreigners were considered as barbarians and therefore the natural enemies of the state. Mistrust of foreigners persists in most cultures.