[2] William of Rubruck described him as about the height of his lord John de Beaumont and as having his entire face covered with reddish spots.

According to Abulghazi, Batu joined Ögedei's military campaign against the Jin dynasty in North China while his younger brother was fighting the Bashkirs, the Cumans, the Bulghars and the Alans in the west.

In the 1230s, Ögedei distributed lands in Shanxi to Batu and the family of Jochi, but they appointed their officials under the supervision of the Imperial governor, and likewise in Khorasan.

[5] At the kurultai in Mongolia after the end of the Mongol-Jin War, the Great Khan Ögedei ordered Batu to conquer western nations.

In 1235 Batu, who earlier had directed the conquest of the Crimean Peninsula, was assigned an army of possibly 130,000[citation needed] to oversee an invasion of Europe.

His relatives and cousins Güyük, Büri, Möngke, Khulgen, Khadan, Baidar and notable Mongol generals Subutai (Subeedei), Borolday, and Mengguser joined him by the order of his uncle Ögedei.

[citation needed] Thereupon Batu Khan divided his army into smaller units, which ransacked fourteen Rus' cities: Rostov, Uglich, Yaroslavl, Kostroma, Kashin, Ksnyatin, Gorodets, Galich, Pereslavl-Zalessky, Yuriev-Polsky, Dmitrov, Volokolamsk, Tver, and Torzhok.

Some modern historians speculate that Batu intended primarily to assure his flanks were safe for the future from possible interference from the Europeans, and partially as a precursor to further conquest.

[citation needed] Having devastated the various Rus' principalities, Subutai and Batu sent spies into Poland, Hungary, and as far as Austria in preparation for an attack into the heartland of Europe.

One group invaded and devastated Poland, defeating a combined force under Henry II the Pious, Duke of Silesia and the Grand Master of the Teutonic Order at Legnica.

The armies swept the plains of Hungary over the summer, and in the spring of 1242 they regained impetus and extended their control into Austria and Dalmatia, as well as invading Morava.

[8] After the siege of Pest, Batu's army withdrew to the Sajo River and inflicted a tremendous defeat on King Béla IV and his allies at the Battle of Mohi on 11 April.

[10] During his campaign in Central Europe, Batu demanded that Frederick II, the Holy Roman Emperor, dethrone himself, and said: "I am coming to usurp your throne instead of you".

[11] The Emperor and Pope Gregory IX called for a crusade against the Mongol Empire, but Europe was plagued by internal strife.

[citation needed] By late 1241, Batu and Subutai were finalizing plans to invade Austria, Italy, and Germany when the news came of the death of Ögedei Khan, who died in December 1241.

[citation needed] The Mongols withdrew in late spring of 1242, as the Princes of the Blood, and Subutai, were recalled to Karakorum where the kurultai was held.

When the Great Khatun Töregene invited him to elect the next Emperor of the Mongol Empire, Batu announced his inability to attend any immediate kurultai, thus delaying the succession for several years.

As one of the oldest members of Chingisid Borjigin, Batu became a viceroy over all the western parts of the empire, controlling routine affairs among the Rus' princes, nominating Jochid retainers as governors of Iran, and receiving in audience grandees from the Caucasus.

[citation needed] During the absence of Batu, the Mongols who were left behind put to death Mstislav, the prince of Rylsk, in Kievan Rus'.

According to the hagiographic vita written in praise of him decades later, Michael replied that he did not object to do obeisance to Batu himself, but to adore images of a dead man was repugnant.

Batu, addressing him, said "You have for a long time refused to come, but have effaced your ill conduct by your obedience" and saluted him with a draught of airag.

Fearing Baiju's aggressive policy, Queen Rusudan of Georgia sent her son David VI Narin to Batu's court to get official recognition as heir apparent.

When Güyük began moving west, Sorghaghtani Beki, the widow of Tolui, warned Batu that he was actually the Great Khan's target.

Batu sent Möngke under the protection of his brothers, Berke and Tukhtemur, and his son Sartaq to assemble a formal kurultai at Kodoe Aral in the heartland.

The supporters of Möngke invited Oghul Qaimish and other main Ögedeid and Chagataid princes to attend the kurultai, but they refused each time, demanding descendants of Ögedei must be khan.

After the assembled throng proclaimed Möngke Great Khan of the Mongol Empire in 1251, he punished the Ögedeid and Chagataid families for the organized plot against him.

[citation needed] During the reign of Möngke, Batu's prestige as kingmaker and viceroy of the great khans in the west reached its height.

Batu's mother Ukhaa ujin belonged to the Mongol Onggirat clan[15] while his chief khatun Boraqchin was an Alchi-Tatar.

Berke did not share Batu's interest in conquering it, however, he demanded Hungarian King Béla IV's submission and sent his general Borolday to Lithuania and Poland.

Long after the expulsion of the Yuan dynasty from China to Mongolia, and the fall of Ilkhanate in Middle East, the descendants of Batu Khan continued to rule the steppes in what is now Ukraine, Russia, and Kazakhstan.