"Applying this same analysis for wars that happened 500 years ago is more difficult" Yes it is and there a still colored discussions about this e.g. consider the Roman expansion in into Greece. There is a camp which argues it was (initally) a defensive move to counter a pact between Macedonia and Selecuid kingdom against Egypt (Green at al), which would distribute the power in eastern Mediterranean against Rome. The other side argues Rome was just build to expand endlessly and it was aggressive move. Here I'm slightly on the first side, as I think Rome wanted to consolidate after the Punic Wars. But after the inital wars the following wars were clearly landgrabs, which provided with Rome with rich areable land in the east. Anyway I argue, to wage war up until to modern times you needed control land as this paid your military, in rome were talking about 50% of state income, most from landtax. And this created the initative to wage war of said reason (we are getting into interstate anarchy theory see. e.g. Eckstein or Waltz).