Ghengis Khan was born in 1167 and died in 1227. He was the person who created the largest empire of that day, bigger than the Roman empire, the Mongol empire.
The Mongols started as a group of tribes which were fighting each other. Eventually, the leader of one of the tribes, Genghis Khan, had enough of this fighting and came to the realization that if they could work together, the tribes would be much more powerful and maybe could conquer their neighbor, China.
Genghis Khan eventually got all the tribes to be friends and then started attacking China. The mongols rode on horses, which meant they were much more mobile than their enemies, so eventually they took over a part of China.
Then, the Mongols started attacking Europe, parts of which they conquered. They also took the land that is today Russia, which was then just a bunch of warring city-states. Finally, the Mongols attacked Japan and for the first time could not take it over.
Then, the Russians banded together, and using their newly-aquired firearms (which the Mongols introduced into Europe and Russia) attacked the Mongols and destroyed their empire, eventually even taking over Genghis Khan's birthplace. Since then, Russia had never been succesfuly invaded.