The end of the Peloponnesian War was when the 421 Truce treaty signed
A lack of central governments with wealth and power
The one and only Adolf Hitler. He was too prideful to lose the war, it would bring great shame to his people, and himself. He didn't want to see that happen, so he took his own life. Would've been cool if it was seppaku, though, wouldn't it? Hope I helped.
The second one, i am sure 78%