For the love of gain would reconcile the weaker to the dominion of the stronger, and the possession of capital enabled the more powerful to reduce th… - Thucydides

It will be enough for me, however, if these words of mine are judged useful by those who want to understand clearly the events which happened in the past and which (human nature being what it is) will, at some time or other and in much the same ways, be repeated in the future. My work is not a piece of writing designed to meet the taste of an immediate public, but was done to last for ever.

Let him remember that many before now have tried to chastise a wrongdoer, and failing to punish their enemy have not even saved themselves; while many who have trusted in force to gain an advantage, instead of gaining anything more, have been doomed to lose what they had. Vengeance is not necessarily successful because wrong has been done, or strength sure because it is confident; but the incalculable element in the future exercises the widest influence, and is the most treacherous, and yet in fact the most useful of all things, as it frightens us all equally, and thus makes us consider before attacking each other.

All these calamities fell upon Hellas simultaneously with the war, which began when the Athenians and Peloponnesians violated the thirty years' truce concluded by them after the recapture of Euboea.
Why they broke it and what were the grounds of quarrel I will first set forth, that in time to come no man may be at a loss to know what was the origin of this great war.

The real though unavowed cause I believe to have been the growth of the Athenian power, which terrified the Lacedaemonians and forced them into war; but the reasons publicly alleged on either side were as follows.

(Book 1 Chapter 23.3-6)