barbaric war lords who destroyed civilizations much the same could be said about Alexanders legacy in Iran and parts of Pakistan and Afghanistan.

In Mongolia and most of Central Asia, Alexander is not seen as a significant figure as he is in Greece or most other countries in the West because he was not part of their history just as Genghis Khan is not part of Western History both Alexander The Great and Genghis Khan are both seen as “Great” where they left their legacy.

It's up to you to decide whether both men deserve their titles as “Great” both built their empires on corpses, pools of blood and the slavery of countless people however both also did good and bought glory for their people, Alexander bought glory for the Greeks and in turn Western Civilization just as Genghis Khan did for the Mongolians and Eastern Civilization.

However their is certainly a difference in how Genghis Khan and Alexander The Great treated the people they conquered , Genghis Khans conquests were much bloodier than Alexanders, Genghis Khans conquests depopulated entire regions like Persia which saw its population go from 2 million to 200,000

 and China which also saw much of its population massacred by Genghis Khan while Alexanders conquest of Persia was cruel there is not any evidence that Alexander caused its population to drastically decline like Genghis Khan did nor is there any evidence that Alexander massacred populations he conquered like Genghis Khan did .

Genghis Khan killed around 20 million to 30 million people while Alexander The Great probably only killed 1 million people if we are really stretching his death toll (The real number is likely 100,000 at most), Alexander The Great left the places he conquered better and rebuilt many cities that he destroyed meanwhile Genghis Khan rebuilt little or no cities and only burned cities (Much more than Alexander ever did in his military career) , Alexander could be cruel but even at his worst he would prefer to enslave a resistant population and would generally spare non-combatants while Genghis Khan did the opposite and ordered his men to kill anyone regardless of if they were solider or civilian .

Nonetheless Most figures who are called “The Great” committed evil , Charlamange who is called “Charles The Great” is glorified by the French and Germans for his conquests and spread of Christianity throughout Germania despite him slaughtering thousands of Saxon Pagans in order to achieve his greatness, Cyrus massacred many thousands in his conquests of Babylon , Media and Lydia yet he is called “The Great” by Iranians and the same goes for most people called “The Great” .

Genghis Khan will always be “The Great” or rather “The Great Khan” to Mongolians and many Easterners just as Alexander will always be “The Great” to Greeks and most Westerners, both men achieved “Great things” even if they did it at the expense of countless lives or the destruction of many civilizations and that's why they are remembered as “The Great” in their respective countries.