Also known as Chinggis Khan, he was the founder and first khagan of the Mongol Empire, which lasted until 1368.
The largest contiguous land empire, Genghis Khan’s territory stretched all the way from the Sea of Japan, through Eastern Europe, and into parts of the Arctic and India. It’s rapid growth came about by Khan and his descendants sending their armies out in every possible direction.
But, as with all things, it didn’t last. Genghis’ grandchildren ended up fighting over the territory, and, after several battles, the territory was split between the survivors.