a new army, which was encircled and totally annihilated by the Mongols in the Battle of the Sit River on March 4. Thereupon Batu Khan divided his army into smaller units, which ransacked fourteen cities of northeastern Rus': Rostov, Uglich, Yaroslavl, Kostroma, Kashin, Ksnyatin, Gorodets, Galich, Pereslavl-Zalessky, Yuriev-Polsky, Dmitrov, Volokolamsk, Tver, and Torzhok. Chinese siege engines were used by the Mongols under Tului to raze the walls of Rus' cities. The most difficult to take was the small town of Kozelsk, whose boy-prince Vasily, son of Titus, and inhabitants resisted the Mongols for seven weeks, killing 4,000. As the story goes, at the news of the Mongol approach, the whole town of Kitezh with all its inhabitants was submerged into a lake, where, as legend has it, it may be seen to this day. The only major cities to escape destruction were Novgorod and Pskov. The Mongols planned to advance on Novgorod, but the principality was spared the fate of its brethren by the decision to preemptively surrender. In mid-1238, Batu Khan devastated the Crimea and pacified Mordovia. In the winter of 1239, he sacked Chernihiv and Pereiaslav. After many days of siege, the horde stormed Kiev in December 1240. Despite the resistance of Danylo of Halych, Batu Khan managed to take two of his principal cities, Halych and Volodymyr. The Mongol Tartars then resolved to "reach the ultimate sea", where they could proceed no further and invaded Hungary (under Batu Khan) and Poland (under Baidar and Kaidu). Batu Khan captured Pest, and then on Christmas Day 1241, Esztergom. Age of Mongol rule The former Rus' principalities became part of the Jochid appanage ruled by Batu. Batu sited a semi-nomadic capital, called Sarai or Sarai Batu (Batu's Palaces), on the lower Volga. The Jochid appanage came to be known as the Golden Horde. For the next three hundred years, all of the Rus' states, including Novgorod, Smolensk, Galich and Pskov, submitted to Mongol rule, except for the Principality of Polotsk. After Mongol and Turco-Mongol suzerainty was fought off, this period of rule by the Golden Horde is commonly referred to negatively by Russian historiography as the Mongol or Tatar "yoke". The Golden Horde Tartars instituted census, taxes, and tributes on the conquered lands, which were usually collected by local princes and brought to Sarai. In the 14th and 15th centuries, with the rise of the Tatar khanates, the slave raids