The Mongol Empire (1206–1368) was the largest contiguous empire in the history of the world, covering 22% of the Earth's total land area with population of 100 million, at its peak.
Their army was built up from squads of ten men each(called an arbat); ten arbats constituted a company of one hundred(called a zuut); ten zuuts made a regiment of one thousand(called myanghan) and ten myanghans would then constitute a regiment of ten thousand (tumen).
Mongols were good at sieges; recruiting artisans and military talents from the cities they conquered, and with Chinese engineers and bombardier corps, were experts in building trebuchets, catapults etc used successfully in European campaigns.
Although famous for horse archers, troops armed with lances were equally skilled.
Discipline distinguished Mongol soldiers from their peers, trained and organized for mobility and speed by being lightly armored.
The Empire began to split after the death of Genghis Khan's grandson Kublai Khan.
So, here's my Mongols (not enough yet, to fight my samurai/korean/chinese playmo-armies)