罗马帝国一旦失去了新奴隶来源，就分裂。蒙古帝国一旦获得了所有骑兵能征服的世界，就崩溃

来源: 于 2021-12-11 09:10:25 [旧帖] [给我悄悄话] 本文已被阅读：次

Rugged individualism worked for cowboys in Indian homeland successfully