Markets!
Viscount Roster felt this was the key.
A long, long time ago, people's settlements were generally near rivers and lakes, or around springs. These places had water sources that could be used for drinking, irrigation, and fishing, meeting basic survival needs.
As these settlements became more and more prosperous, gradually some settlements' food supplies became more abundant, creating the need for trade.
Choosing places with relatively convenient transportation, where both sides' tribes or even multiple tribes could easily reach, markets gradually formed.
And these markets, as their scale continuously expanded, became towns, then major cities, continuing right up to the present day.
In other words, most cities and towns in this world originated as markets with convenient transportation. Only those built on strategic passes as military fortresses were established for other purposes.
