Final answer:
Genghis Khan's reputation was solidified as a formidable conqueror after his capture of the Jin capital, Zhongdu, marked by the extensive looting and enslavement, furthering the expansion of the Mongol Empire and reshaping the course of history.
Step-by-step explanation:
After Genghis Khan took over the Jin Empire, his reputation was that of a powerful and efficient conqueror. Chinggis Khan exploited weaknesses of the Jin Empire, enlisting the help of their linguistic cousins, the Khitan, who resented the Jurchen Jin dynasty. With these defectors bolstering his army, the Mongols laid siege to the Jin capital, Zhongdu, capturing it and ordering a thorough looting. Tens of thousands were enslaved and untold numbers massacred, reinforcing Genghis Khan's fearsome reputation.
In subsequent years, Genghis Khan continued his campaigns to reassert control over his conquests and punish disloyalty, as seen with the Xi Xia. The vast wealth seized from the Jin changed the Mongol leadership's mindset, pushing them to seek more resources and raid further west. The conquests spread the Mongol Empire's reach significantly, with their territories ultimately extending from the Korean Peninsula to Central Asia, the border with the Islamic world, and beyond. Genghis Khan's successful military campaigns and his empire's expansion significantly altered world history, setting the stage for the modern era to emerge.