section_path: History/Death of Genghis Khan and expansion under Ögedei (1227–1241)/Invasions of Kievan Rus' and central China
section_name: Invasions of Kievan Rus' and central China
paragraph_text: Invasions of Kievan Rus' and central China
  
  Meanwhile, in an offensive action against the Song dynasty, Mongol armies captured Siyang-yang, the Yangtze and Sichuan, but did not secure their control over the conquered areas. The Song generals were able to recapture Siyang-yang from the Mongols in 1239. After the sudden death of Ögedei's son Kochu in Chinese territory the Mongols withdrew from southern China, although Kochu's brother Prince Koten invaded Tibet immediately after their withdrawal.
  
  Batu Khan, another grandson of Genghis Khan, overran the territories of the Bulgars, the Alans, the Kypchaks, Bashkirs, Mordvins, Chuvash, and other nations of the southern Russian steppe. By 1237 the Mongols were encroaching upon Ryazan, the first Kievan Rus' principality they were to attack. After a three-day siege involving fierce fighting, the Mongols captured the city and massacred its inhabitants. They then proceeded to destroy the army of the Grand Principality of Vladimir at the Battle of the Sit River.
  
  The Mongols captured the Alania capital Maghas in 1238. By 1240, all Kievan Rus' had fallen to the Asian invaders except for a few northern cities. Mongol troops under Chormaqan in Persia connecting his invasion of Transcaucasia with the invasion of Batu and Subutai, forced the Georgian and Armenian nobles to surrender as well.
  
  Giovanni de Plano Carpini, the pope's envoy to the Mongol great khan, travelled through Kiev in February 1246 and wrote:
  
  They attacked Russia, where they made great havoc, destroying cities and fortresses and slaughtering men; and they laid siege to Kiev, the capital of Russia; after they had besieged the city for a long time, they took it and put the inhabitants to death. When we were journeying through that land we came across countless skulls and bones of dead men lying about on the ground. Kiev had been a very large and thickly populated town, but now it has been reduced almost to nothing, for there are at the present time scarce two hundred houses there and the inhabitants are kept in complete slavery.
  
  Despite the military successes, strife continued within the Mongol ranks. Batu's relations with Güyük, Ögedei's eldest son, and Büri, the beloved grandson of Chagatai Khan, remained tense and worsened during Batu's victory banquet in southern Kievan Rus'. Nevertheless, Güyük and Buri could not do anything to harm Batu's position as long as his uncle Ögedei was still alive. Ögedei continued with offensives into the Indian subcontinent, temporarily investing Uchch, Lahore, and Multan of the Delhi Sultanate and stationing a Mongol overseer in Kashmir, though the invasions into India eventually failed and were forced to retreat. In northeastern Asia, Ögedei agreed to end the conflict with Goryeo by making it a client state and sent Mongol princesses to wed Goryeo princes. He then reinforced his kheshig with the Koreans through both diplomacy and military force.