Late in the life of Genghis Khan, members of his family fought over who was to be his heir. To end the dispute, Genghis Khan chose his third son, Ogodei (pronounced oh-go-day). And in 1229, after Genghis Khan's death, a great Mongol assembly confirmed the succession of Ogodei as the Great Khan. Ogodei began his rule aiming to live up to his mandate as ruler of the world.  In earnest he began drafting conquered people into his armies. About one in ten young men from agricultural societies went into the Mongol infantry or to assist in siege warfare against fortified cities. And tent dwellers (nomadic herdsmen) joined the Mongol cavalry.

In 1231, Ogodei sent an army to police Korean defiance of an agreement made in 1218 to pay annual tribute. In 1232 the Koreans rebelled and a struggle ensued that was to last for decades. Ogodei also sent his armies against the Jurzhen, and in 1234 his armies completed the conquest of northern China. In the mid-thirties Ogodei sent armies against Slavic principalities in Eastern Europe, but resistance by the Asiatic tribes between the Volga and Ural rivers was greater than he had expected, delaying for several years his plans of conquest west of the Ural Mountains.

Finally in 1237 his army pushed against the Russians, conquering the cities of Vladimir,  Kolmna and Moscow in 1238. In 1240 his army destroyed the city of Kiev.

At Liegnitz (in what is now Poland) although outnumbered, his army destroyed a German army of heavily armored knights. His army pushed through Hungary, and in 1241 it reached the outskirts of Vienna. Then, mysteriously to Europeans, the Mongols pulled back from Vienna  -- while holding onto overlordship in Russia and other conquered territories. To the Europeans it seemed as though they were saved by a miracle. To the Mongols it was something different. The Mongol retreat from central Europe was in response to  Ogodei's death. High ranking army leaders believed they had to return to confirm the selecting of a new ruler.

Ogodei had been like a lot of sons of men who had fought their way to power and established a dynasty -- something less than his father. Ogodei  had been a profligate spender of money, burdening his conquered subjects with unpredictable increases in taxes for his sudden needs of money. And torn between duty and his having tired of it, Ogodei had begun drinking so heavily that a functionary had been assigned to count the number of wine goblets that he emptied daily.  He had died at the age of fifty-six after a binge of drinking during a hunting trip.

However burdensome, there was no shortage of  young men from Genghis Khan's extended family eager to become the next Great Khan. Ogodei's widow, Töregene, began administering  Ogodei's estate, ruling her late husband's realm in his name and acting as regent for her eldest son. Military operations slowed, including a reprieve of the fighting in Korea. Fighting began among men in the extended family.  In 1246, one of them, Güyüg, was able to buy support and win selection as  Ogodei's successor. He showered gifts on people whose support he continued to seek, from princes to lowly scribes, as if money was in endless supply. He became heavily indebted to merchants and his short reign came to an end in 1247.

This was not before Pope Innocent IV sent an envoy to the Great Khan, asking him not to invade Europe and believing that he could be converted to Roman Christianity. The new Great Khan adhered to the standing belief that it was the leader of the Mongols who had the right to rule the world, and he replied to the Pope, demanding his submission.

The selection of the new Great Khan went to Mongke, another of Genghis Khan's grandsons. A plot by rivals to assassinate him at his coronation was uncovered, and this was followed by torture, purges, trials, confessions and much letting of blood -- purges within the royal family as well as among government officials. Mongke attempted to establish efficiency in governing all of his subjects. The postal relay system was freed of being jammed by elites using it for their personal benefit. He established predictable taxation that permitted planning by growers. He demanded that local rule not interfere with productive work. The death penalty was to apply to officers who seized vegetables from the gardens of Chinese peasants. Princes were forbidden to issue orders without approval from the imperial court. Officials, civil and military, were forbidden to enter areas where they had no jurisdiction. Military campaigning was to be done without devastating agricultural land or devastating cities, actions seen as reducing potential tax revenues for the imperial treasury. Private property was to be respected. Theft and brigandage were to be punished, with death the punishment even for minor offenses.