Boroldai Boroldai ( or Burulday , Borolday ) , also known as Burundai , ( Cyrillic : " Боролдай " ) ( died 1262 ) was a notable Mongol general of the mid 13th century . He participated in the Mongol invasion of Russia and Europe in 1236 - 1242 . The clan of Borolday is not clear . He was probably from one of four tribes that Chinggis Khaan ( 1162 – 1227 ) assigned to his eldest son , Jochi : the Sanchi ' ud ( or Salji ' ud ) , Keniges , Uushin , and Je ' ured clans . Serving under Jochi ' s successor and son , Batu Khan , Borolday ' s vanguard surprised and crushed the great army of Yuri II , the Grand Prince of Vladimir , at the battle of the Sit River in 1238 . He also participated in the Siege of Kiev in 1240 . After the conquest of Rus , the Mongols invaded Eastern and eastern Central Europe . His name appears as Bujgai or Bujakh in " The Secret History of the Mongols " . According to " The Secret History of the Mongols " , Ögedei , Khagan of the Mongol Empire , praised Subutai and Bujgai ' s merit when he blamed his son Güyük ' s arrogant behaviour . Borolday assisted Subutai to prepare the strategy of the final assault during the Battle of Mohi ( 1241 ) . Borolday ' s division directly attacked the main camp of King Béla IV of Hungary . Batu ' s brother Shiban ' s vanguard supported this attack . After a very hard fight , Batu ' s army crushed the Hungarians and their allies , Croats and Templar Knights at Mohi on April 11 , 1241 . During the succession struggle over the throne of the Mongol Empire in early 1251 , 100 , 000 Jochid troops under Borolday were stationed near Otrar to keep an eye on the Chagatayids who allied with the Ögedeids against Batu ' s cousin and ally , Möngke . In 1255 , Daniel of Galicia revolted against the Mongol rule . He repelled the initial Mongol assault under Orda ' s son Quremsa . Berke replaced Quremsa , son of his eldest brother , Orda , with the much experienced Borolday . The latter led a force that overcame the resistance of Danylo of Halych in 1259 . According to some sources , Daniel fled to Poland leaving his son and brother at the mercy of the Mongol army . He may have hidden in the castle of Galicia instead . The Mongols needed to halt Poland ' s aid to Daniel and war booty to fed the demand of their soldiers . Boroldai forced him to demolish all walls of cities in Galich and Volhynia . The Mongols knew that the Lithuanians raided Mongol vassals , Smolensk and Torzhok , in the previous year . Alongside Nogai Khan , Boroldai led a punitive expedition against the Grand Duchy of Lithuania . The Mongols attacked Lithuania , but the Lithuanians fled before the decisive battle . After pillaging several villages and towns in Lithuania , Borolday returned to Galich and demanded Daniel to assist his battle against the Poles . The Rus soldiers under Daniel ' s son , Lev , and brother , Vasily , joined the Mongol expedition . Lublin , Sieradz , Sandomierz , Zawichost , Kraków , and Bytom were ravaged and plundered by Mongol army . Berke had no intention of occupying or conquering Poland . After this raid Pope Alexander IV tried without success to organize a crusade against the Tatars . After 1259 , Boroldai ' s name does not appear again in Russian annals . A general named Burulday was killed in the battle at the Terek River on January 13 , 1263 , during the Berke – Hulagu war . This may have been Boroldai . His name appears in the opera " The Legend of the Invisible City of Kitezh and the Maiden Fevroniya " by Nikolai Rimsky - Korsakov , and in Mongolian fairy tales .