Genghis Khan

When Genghis Khan sent a trade caravan to the Khwarazmian Empire, the governor of one city seized it and killed the traders. Genghis Khan retaliated by invading the empire with 200,000 men and killing the governor by pouring molten silver down his eyes and mouth. Genghis Khan even went so far as to divert a river through the Khwarezmid emperor's birthplace, erasing it from the map.