History of the Peloponnesian War

The sufferings which revolution entailed upon the cities were many and terrible, such as have occurred and always will occur, as long as the nature of mankind remains the same; though in a severer or milder form, and varying in their symptoms, according to the variety of the particular cases. In peace and prosperity states and individuals have better sentiments, because they do not find themselves suddenly confronted with imperious necessities; but war takes away the easy supply of daily wants, and so proves a rough master, that brings most men's characters to a level with their fortunes.

Revolution thus ran its course from city to city, and the places which it arrived at last, from having heard what had been done before carried to a still greater excess the refinement of their inventions, as manifested in the cunning of their enterprises and the atrocity of their reprisals.