defeat left the Rus' principalities at the mercy of invaders, the Mongol or Tartar forces retreated and did not reappear for thirteen years, during which time the princes of Rus' went on quarreling and fighting as before, until they were startled by a new and much more formidable invading force. In The Secret History of the Mongols, the only reference to this early battle is: Invasion of Batu Khan The vast Mongolian Great Khanate army of around 40,000 mounted archers, commanded by Batu Khan and Subutai, crossed the Volga River and invaded Volga Bulgaria in late 1236. It took them only a month to extinguish the resistance of the Volga Bulgars, the Cumans-Kipchaks and the Alans. Immediately prior to the invasion, Friar Julian from Hungary had travelled to the eastern border of the Rus' and learned of the Mongol army, which was waiting for the onset of winter so that they could cross the frozen rivers and swamps. In his letter to the Pope's legate in Hungary, Julian described meeting Mongol messengers who had been detained by Yuri II of Vladimir-Suzdal on their way to Hungary. Yuri II gave their letter to Julian. In November 1237, Batu Khan sent his envoys to the court of Yuri II and demanded his submission. According to the Laurentian Codex, the Mongols actually came seeking peace, but Yuri II treated them with disdain: Regardless of what impression Yuri II may have given the Mongol delegations, of which several are mentioned, he did his best to avoid direct conflict. He sent them away with what were described as gifts, which were essentially tribute or bribes to keep them from invading. The Mongols attacked from several directions. One section attacked Suzdal, one from the Volga, and another from the south towards Ryazan. According to Rashid al-Din Hamadani, the Siege of Ryazan was conducted by Batu, Orda, Güyük, Mengu Qa'an, Kulkan, Kadan, and Buri. The city fell after three days. Alarmed by the news, Yuri II sent his sons to detain the invaders, but they were defeated and ran for their lives. Yuri II also fled Vladimir for Yaroslavl. Having burnt down Kolomna and Moscow, the horde laid siege to Vladimir on February 4, 1238. Three days later, the capital of Vladimir-Suzdal was taken and burnt to the ground. The royal family perished in the fire, while the grand prince retreated northward. Crossing the Volga, Vladimir mustered