Genghis Khan rarely left a score unsettled

While Genghis Khan frequently offered other nations the chance to voluntarily submit to Mongol authority, he wasn't afraid to use the sword against any society that resisted. After the Shah of the Khwarezmid Empire brokered a truce with the Mongols in 1219, one of his most well-known campaigns of vengeance was launched.

When Genghis' initial messengers were assassinated, the furious Khan retaliated by unleashing the entire force of his Mongol hordes on the Khwarezmid domains in Persia. Genghis had offered the Shah a rich trading arrangement to exchange products along the Silk Road. Millions of people died in the ensuing fight, and the Shah's realm was completely destroyed, but the Khan didn't stop there.

After his victory, he went back to the east and waged war against a tribe of Mongol subjects known as the Tanguts of Xi Xia who had defied his order to supply them with soldiers for his invasion of Khwarizm. The Great Khan commanded the execution of the whole Tangut royal family as retribution for their disobedience after routing the Tangut soldiers and sacking their capital.