The Mongols
The Mongol Empire was a powerful force in 1206 CE. It was founded by a man called Temujin, who was a rather obscure nomad in the steppes of modern-day Mongolia. His name, Genghis Khan, is the anglicized version of his Mongolian title granted after he came of age, Chinggis Khan. He managed to found one of the largest contiguous empires in history, over nine million square miles, spreading over all of Asia and even extending into Europe. The Mongols were a ruthless clan of nomads who killed hundred of millions of people in their heyday. The beginnings of this Golden Horde, as they were known, were slightly more humble - Genghis Khan was the leader of a small clan in the steppes who, through virtue of his knowledge of law and combat, became the ruler of two other tribes: the Jurchen and Tangut. The only reason he began turning against the rest of the Asian area was because the Shah of Kwarezm stole his traded goods and killed the Mongol ambassadors.
By the time Genghis Khan was around sixty, the Mongols held a massive position over Asia - the furthest reach of their Horde was (in modern-day terms) Poland. Unfortunately for the Empire, Genghis Khan died of a heart attack at sixty-five, and Mongol burial traditions demanded that he be buried next to his father, all the way back in the steppes. Due to this, the Mongols lost a lot of ground and the people began rebelling. Despite the Empire being split between Genghis' grandsons (Ogdei, Kublai, Mongke, and Guyuk), it still collapsed after less that 200 years of power.
By the time Genghis Khan was around sixty, the Mongols held a massive position over Asia - the furthest reach of their Horde was (in modern-day terms) Poland. Unfortunately for the Empire, Genghis Khan died of a heart attack at sixty-five, and Mongol burial traditions demanded that he be buried next to his father, all the way back in the steppes. Due to this, the Mongols lost a lot of ground and the people began rebelling. Despite the Empire being split between Genghis' grandsons (Ogdei, Kublai, Mongke, and Guyuk), it still collapsed after less that 200 years of power.