History of the Peloponnesian War

With regard to the former, it were difficult even in time of peace to set up a rival city; much more in a hostile country, and when we should have raised works no less against them:

and if they build [only] a fort, they might perhaps hurt some part of our land by incursions and [*]( i.e. by harbouring the slaves and others who might go over to them.) desertions; it will not, however, be possible for them to prevent our sailing to their country and raising forts, and retaliating with our ships, in which we are so strong.

For we have more advantage for land-service from our naval skill, than they have for naval matters from their skill by land.

But to become skilful at sea will not easily be acquired by them.