Haven't heard of the Mongols, hey?
...what? Assuming you're referring to the well-known empire, Mongols were extremely authoritarian. In the entire history of Earth, there has never been an event in which libertarians or anyone with a similar social structure fielded a military of any kind. Fighting on a large scale requires tactics and strategy, which requires one or more individuals commanding others in an authority structure. The Romans knew this. The Mongols knew this. The motherfucking Vandals knew this. Maybe you should know it, too.
While they did have social structures (obviously, a Khan/Emperor), the Mongol military, especially in the early days, were pretty autonomous. It's difficult to associate modern libertarianism with their military and society, but relative to the various Chinese, Arabic and European civilizations that they fought, the Mongols were much less authoritarian.
This is kind of what I'm trying to say.
But we're getting off topic now.