to lead an extraordinary campaign into southern Russia, which would be staged largely in the winter months. Three years, and numerous victories later, they returned to rendezvous with the main Mongol force and to contribute in the war against the Ch'in and their Muslim enemies. Mongol children were taught to ride on horseback from the age of three, and were given bow and arrows to use for hunting at the age of five. Horseback became a natural way for the Mongols to conduct war. When speed was essential, a Mongol rider could even sleep while in the saddle; and by using a system that consisted of approximately four remounts, Temujin's army was capable of traversing 130 miles in two days, with no breaks for food. Another defining characteristic of a Mongolian army was the speed and voracity with which it was able to accept and prepare for battle. The Mongol's harsh, nomadic lifestyle had prepared them well for the rigors of war; and they often thrived in conditions that would be considered intolerable by any other military of its time. When the need arose they could last up to ten days at a time without cooking food, during which they would sustain themselves by drinking the blood of their horses. Every victory wrought by the Mongols was followed by slaughters of incredible scale. No citizens, with the exception of those who were useful to the Mongol war effort, were spared in these attacks. In 1221 AD, the Islamic city of Merv was captured; 700,000 were murdered, and a rearguard was assembled to dispatch any citizens who were fortunate enough to have escaped the original slaughter, this was routine for the Mongol army. By the end of the 13th century Mongol armies had been involved in action in countries including: Poland, Japan, Korea, Hungary, Russia, Palestine, Persia, India, Cambodia, Burma, and Vietnam. After Temujin's death in 1227 five more Khans would follow, including, Kublai Khan, whose triumph was the union of all of China under his rule. However, the death of Kublai Khan in 1294 AD marked the end of an era for Mongol conquests, and the march of Mongol armies was never again resumed, leaving its populace to be absorbed into the sedentary life style of the neighboring people.