Thucydides of Athens wrote the war of the Peloponnesians and the Athenians, how they waged it against each other. He began writing at its very outset, in the expectation that this would be a great war and more worthy of account than any previous one. He based this judgement on the grounds that both sides came into the war at the height of their powers and in a full state of military readiness; and he also saw that the rest of the Greek world had either taken sides right at the start or was now planning to do so. This was certainly the greatest ever upheaval among the Greeks, and one which affected a good part of the barbarian world too – even, you could say, most of mankind. In respect of the preceding period and the still remoter past, the length of time that has elapsed made it impossible to ascertain clearly what happened; but from the evidence I find I can trust in pushing my enquiries back as far as possible, I judge that earlier events were not on the same scale, either as regards their wars or in other respects.

It is evident that long ago what is now called ‘Hellas’ had no stable settlements; instead there were various migrations in these early times and each group readily abandoned their own territory whenever forced to do so by those with superior numbers. For there was no commerce and people were insecure about making contact with each other either by land or sea, so they each lived off their own land just at subsistence level and neither produced any surplus goods nor planted the ground, since they had no walls and never knew when some invader might come and rob them. They took the view that they could secure their daily needs for sustenance anywhere, and so were not exercised about uprooting and moving on, with the consequence that they had no cities of any size or other general resources to make them strong.