The Mongols were a nomadic people living in the steppes to the north and east of China. Before 1200 the various tribes fought mainly amongst themselves. In the late 1100s and early 1200s a leader named Temujin created a confederation of tribes after defeating the Tartars to the east. In 1206, at the age of 42, Temujin took the title Universal Ruler, which translates to Genghis Khan.
In 1209 Genghis Khan was ready to take on the world , He attacked the Western Hsia (Xi Xia) one of the neighbouring states in northern China. The Mongols besieged their capital, Yinchuan, and tried to flood it. The Tangut emperor submitted to Genghis, handing over tribute and his daugher's hand in marriage. Genghis went off to try his luck with the Chin (Jin) empire and then the rest of the world.
In the spring of 1211, Genghis Khan advanced across the Gobi desert and defeated a large Jin army at a pass called Huan-erh-tsui - the Badger's Mouth. The Jin retreated to their capital, Beijing. Soon their second city, Mukden, was taken and in 1214, Beijing fell. By then the Jin emperor had moved his capital to Bianjing on the site of modern Kaifeng.
In 1217 Genghis returned to Mongolia. He wished to trade with the lands to the west, particularly the Islamic empire of Khwarezm, which extended from Persia to Transoxiana. However the Khwarezm Shah seized a caravan sent by the Mongols and killed Genghis Khan's envoys.
Genghis attacked, driving through Transoxiana besieging and then destroying cities such as Bukhara and Samarkand. The Mongols continued into Persia, Azerbaijan and Armenia. They reached Crimea on the north coast of the Black Sea. From there they met Prince Mstitslav of Kiev with his army of 80,000. At the battle of Kalka River in 1223, the Prince's army was routed.
In 1225, Genghis Khan returned to Mongolia. He now ruled everything between the Caspian Sea and Korea. During his conquests, the Tangut of Western Hsia had refused him troops when requested. He decided to finish them off. However, in 1227, at the age of sixty-five, while campaigning against the Tangut, Genghis Khan fell off his horse and died. He was buried at a secret location. It was left to his successors to finish off the Tangut and the rest of China.