Plato on Immigration

     "The intercourse of cities with one another is apt to create a confusion of manners;  strangers are always suggesting novelties to strangers.  When states are well governed by good laws the mixture causes the greatest possible injury;  but seeing that most cities are the reverse of well-ordered, the confusion which arises in them from the reception of strangers, and from the citizens themselves rushing off into other cities, when any one either young or old desires to travel anywhere abroad at whatever time, is of no consequence.  On the other hand, the refusal of states to receive others, and for their own citizens never to go to other places, is an utter impossibility, and to the rest of the world is likely to appear ruthless and uncivilized;  it is a practice adopted by people who use harsh words, such as xenelasia or banishment of strangers, and who have harsh and morose ways, as men think."  Plato Laws Book XII Paragraph 950.