In Cicero’s Republic, he is having Scipio Africanus hold forth on the history of Rome, and how that history fashioned the Roman constitution, which is the best constitution (lots of people know this, ahem), and we come upon this gem: 

Furthermore, the moral character of coastal cities is prone to corruption and decay. For they are exposed to a mixture of strange talk and strange modes of behavior. Foreign customs are important along with foreign merchandise; and so none of their ancestral institutions can remain unaffected. The inhabitantants of those cities do not stay at home. They are always dashing to foreign parts, full of airy hopes and designs. And even when, physically, they stay put, they wander abroad in their imagination.

(P37, Oxford World’s Classics edition, Niall Rudd, translator)