I believe you’re projecting your modern assumptions about how the world worked in “savage” antiquity. The Peloponesian War began with a dispute with Athens ove

I believe you’re projecting your modern assumptions about how the world worked in “savage” antiquity. The Peloponesian War began with a dispute with Athens over the government of Corinth’s ancient (at least 400 years at this point) Adriatic colony of Cocyra. There is today in the museum of the Acropolis a stele recording a treaty between Cocyra and Athens agreed during this crisis. Corinth maintained mother-city ties - and disputed Athen’s influence. Later in the same war, the Athenians launched an ambitious invasion of Sciliy, pursuing empire against their enemy Sparta’s ally Syracuse (and other cities of Magna Grecia). After the war, a multinational Greek force famously marched all the way to Mesopotamia as mercenaries (and only a few generations later Alexander would come the same way). Those mercenaries were saved when the returned to the very edge of the Greek sphere at Trebizond (Thallata! Thallata!). From there they were plugged back in to a network of communication, commerce and diplomacy that stretched all the way down the Mediterranean to Marsielle (the colony of Marsala). This diplomacy and internationalism of the Classical Greek Mediterranean was a change from the dark ages of the Bronze Age collapse, where a colony may indeed be another world. But before that there was another cosmopolitan period of treaties and internationalism (of a sort). We associate that period with the relations between Mesopotamian states (Akkad etc), Mediterranean states (Egypt, Knossos, Acheans) and Anatolian states (Hitties, Hurrians, etc). Complex diplomacy between these states is recorded in cuneiform clay.