Listen to Dan Carlin's Hardcore history podcast about the Mongols
It's truly fascinating.
http://www.dancarlin.com/product/hardcore-history-43-wrath-of-the-khans-i/
The people's of the steep and the Altai Mountain where always very strong warriors, pretty much having the best Calvary archers, almost no logistics and superior battlefield tactics.
But they are very tough to unite as they fight constantly among themselves.
Throughout history, surrounding areas feared that these people would eventually unite.
In China this happened around 200bc. The Xiongnu untied and initially defeated the Han and made them a vassal for several years before the Han where able to defeat the Xiongnu and make them the vassal this time.
Please remember at this time China was very huge. The Han Dynasty and the Roman Empire are somewhat comparable in terms of population and size.
This also later happened when the Huns united various people and wrecked havoc in Europe. The Huns collapsed very shortly too because of their inability to stay united after they suffered a defeat from the Romans.
So China and the other powers played the Nomads/Steppe people against each other. They were hard to unite so it was rather easy for the main powers to get them to fight each other.
The great wall of china was built specifically to stop these people.
So everything was good for awhile...
there are no huge-successful nomad confederation for quite some time.
At least not the likes what they are about to experience.
The Mongols were extremely adaptive and were constantly adding new tactics they learned from the people they conquered.
The mongols were the world's worst nightmare come true. And it is truly fascinating on how they were able to conquer, govern, and strike fear in much of the world.