55 Days. 1,320 Hours. 79,200 Minutes.
There are two groups that essentially came from nowhere during this period. One was the Arabs. The next, The Mongols.
This era has SEVEN empires to know. However, not all empires are created equal. The two most important in this era are the Muslims & Mongols.
The Mongols created the most impressive land based empire in the history of the planet. There is too much to say about them here.
OR... If you want to know EVERYTHING about the Mongols and have several hours to spare. Go to the G.O.A.T. : DAN CARLIN's HARDCORE HISTORY