The animal that changed their ways was the horse.
Answer: What exactly are you asking?
Explanation:
Post-war, all of the combatants were rather weighed down by large amounts of debt they had accumulated during the war. This, combined with rapid overproduction of currency, caused hyperinflation and doomed global economies, later leading to the Great Depression.
Answer:
Offer them power and riches if they joined peacefully. Invade them immediately with their large army.
