Battle of Mohi The Battle of Mohi ( today Muhi ) , also known as Battle of the Sajó River or Battle of the Tisza River ( 11 April 1241 ) , was the main battle between the Mongol Empire and the Kingdom of Hungary during the Mongol invasion of Europe . It took place at Muhi , southwest of the Sajó River . After the invasion , Hungary lay in ruins . Nearly half of the inhabited places had been destroyed by the invading armies . Around 15 – 25 percent of the population was lost , mostly in lowland areas , especially in the Great Hungarian Plain , the southern reaches of the Hungarian plain in the area now called the Banat and in southern Transylvania . Background . The Mongol invasion of Europe . The Mongols attacked Hungary with three armies . One of them attacked through Poland in order to withhold possible Polish auxiliaries and defeated the army of Duke Henry II the Pious of Silesia at Legnica . A southern army attacked Transylvania , defeated the voivod and crushed the Transylvanian Hungarian army . The main army led by Khan Batu and Subutai attacked Hungary through the fortified Verecke Pass and annihilated the army led by Denis Tomaj , the count palatine on 12 March 1241 . Warnings and Hungarian preparation . In 1223 the expanding Mongol Empire defeated an allied Cuman army at the Kalka River . The defeated Cumans retreated towards Hungary . Hungary had tried to convert the Cumans to Christianity and expand its influence over them for several decades beforehand . The Hungarian King Béla IV even began to use the title " King of Cumania " . When Cuman refugees ( ca . 40 , 000 people ) sought asylum in his kingdom , it seemed that at least a portion of the Cumans had accepted Hungarian rule . The Mongols saw Hungary as a rival , and the Cuman migration to Hungary as a casus belli . In their ultimatum they also blamed Hungary for " missing envoys " . The Mongolian threat appeared during a time of political turmoil in Hungary . Traditionally , the base of royal power consisted of vast estates owned as royal property . Under King Andrew II , donations of land to nobles by the crown reached a new peak : whole counties were donated . As Andrew II said , " The best measure of royal generosity is measureless " . After Béla IV inherited his father ' s throne he began to reconfiscate Andrew ’ s donations and to execute or expel his advisers . He also denied the nobles ' right of personal hearings and accepted only written petitions to his chancellery . He even had the chairs of the council chamber taken away in order to force everybody to stand in his presence . His actions caused great disaffection among the nobles . The newly arrived and grateful Cumans gave the king more power ( and increased prestige with the Church for converting them ) but also caused more friction . The nomadic Cumans did not easily integrate with the settled Hungarians and the nobles were shocked that the king supported the Cumans in quarrels between the two . King Béla began to mobilise his army and ordered all of his troops , including the Cumans , to the city of Pest . Frederick II Babenberg , Duke of Austria and Styria , also arrived there to help him . At this moment , the conflict between Cumans and Hungarians caused riots and the Cuman khan – who had been under the personal protection of the king – was murdered . Some sources mention the role of Duke Frederick in inciting this riot , but his true role is unknown . The Cumans believed that they had been betrayed , and left the country to the south , pillaging all the way . The full mobilisation was unsuccessful ; many contingents were unable to reach Pest ; some were destroyed by Mongols before they arrived , some by renegade Cumans . Many nobles refused to take part in the campaign because they hated the king and desired his downfall . Hardly anybody believed that the Mongol attack was a serious threat to the kingdom ' s security , and the Cuman defection was considered minor and usual . This attitude may have contributed to the death of the Cuman Khan Kuthen . The battle . Initial actions . The Mongol vanguard reached Pest on 15 March and began to pillage the neighbouring area . King Béla forbade his men to attack them , as the Hungarian army was still unprepared . Even so , Duke Frederick attacked and defeated a minor raiding party – so Béla came to be seen as a coward . After this " heroic " act , Duke Frederick returned home . Ugrin Csák , the archbishop of Kalocsa , also tried to attack a Mongol contingent , but he was lured to a swamp and his armoured cavalry became irretrievably stuck in it . He barely escaped with his life . Finally , the king decided to offer the Mongols battle , but they began to retreat . This affirmed the opinion of the nobles that the Mongols were not a threat and the king ’ s behaviour was not cautious but cowardly . After a week of forced marches and frequent Mongol attacks , the Hungarian army reached the flooded River Sajó , where it stopped to rest and to wait for additional supplies . The king and the Hungarians still did not know that the main Mongol army , which numbered between 20 , 000 and 30 , 000 – in contrast to the approximately 15 , 000 - strong collection of varied Hungarian forces – was present , because of the wooded terrain on the far bank of the Sajó . The cautious king ordered the building of a heavily fortified camp of wagons . The Mongol plan . It is highly unlikely that the Mongols originally wanted to cross a wide and dangerous river to attack a fortified camp . It is more likely that their original plan was to attack the Hungarians while crossing the river , as in the Battle of the Kalka River , although this is still not certain . A Ruthenia n slave of the Mongols escaped to the Hungarians and warned them that the Mongols intended a night attack over the bridge over the Sajó . The Mongols planned to bring their three contingents together if possible before engaging in battle and watched for signs that the Hungarians planned to attack . The way the camp was fortified was a tactical error since this would impede moves to escape in the event of an attack . Fight at the Sajó bridge . The Hungarians still did not believe that there would be a full - scale attack , but the troops of Prince Kálmán , Duke of Slavonia and younger brother of King Béla , and Archbishop Ugrin Csák with Rembald de Voczon , the Templar master , left the camp to surprise the Mongols and defend the unguarded bridge . They reached the bridge at midnight , having marched the last seven kilometres in darkness ( the sun having set at 18 : 29 ) . It is very unlikely that the Mongols wanted to attack at night ( horse archers avoid night battles ) , but they wanted to cross the river to be able to attack the Hungarian camp at dawn . When Kálmán and Ugrin arrived they found the Mongols unprepared and in the middle of crossing the bridge . They successfully forced them into battle and achieved a victory there . The Mongols had been unprepared for the crossbowmen , who had inflicted considerable losses on them , helped by the size of the bridge , which was a minimum of 200 meters long . The Hungarians left some soldiers to guard the bridge and returned to the camp , unaware that the main Mongol army was nearby . Arriving at the camp at around 02 : 00 , they celebrated their victory . Main battle . Morning . The unexpected Hungarian victory forced the Mongol generals to modify their plans . Sejban was sent north to a ford with a smaller force to cross the river and attack the rear of the bridge - guard . At about 04 : 00 , as daylight started to break , they began the crossing . Meanwhile , Subutai went south to build a makeshift emergency bridge while the Hungarians were engaged at the main bridge , but left Batu a plan to use giant stone throwers to clear the crossbowmen opposing them . At dawn , Batu , with the help of seven stone thrower s , attacked the Hungarian guards on the bridge . When Sejban and his men arrived , the Hungarians retreated to their camp . The Mongol main forces finished crossing the river around 08 : 00 . When the fleeing Hungarians arrived at the camp they woke the others . Kálmán , Ugrin and the Templar master then left the camp again to deal with the attackers . Others remained there , believing this was also a minor attack and that Prince Kálmán would again be victorious . But as Kálmán and Ugrin witnessed the horde of Mongols swell , they realised that this was not a minor raid but an attack by the main Mongol force . After some heavy fighting they returned to the camp hoping to mobilise the full army . They were badly disappointed , as the king had not even issued orders to prepare for the battle . Archbishop Ugrin reproached the king for his faults in public . Finally the Hungarian army sallied forth , but this delay gave Batu enough time to finish the crossing . A hard struggle ensued . The Hungarians outnumbered Batu ' s troops and the Mongols were unable to move quickly because the Sajó was behind their backs . The " History of the Yuan Dynasty " ( " Yuan shi " ) mentions that Batu lost thirty of his baaturs ( heavily armoured bodyguards ) and one of his lieutenants , Bakatu , when he personally assaulted a strong point with the vanguard . At this moment , Subutai who had been delayed by bridge - building , attacked the Hungarians ’ rear flank , causing them to retreat in panic to their camp . Afternoon . It is possible that the Hungarians might have had the capability to defend the camp , but their sallies were ineffective , and they were terrified by the flaming arrows , resulting in the deaths of many soldiers by the trampling crush of their comrades . Finally , the demoralised soldiers were routed . They tried to escape through a gap left open on purpose by the Mongols , because fleeing soldiers can be killed more easily than those who , with their backs to a wall , are forced to fight to the death . Mongol casualties had been so great that , at this point , Batu did not want to pursue the Hungarians . However , Subutai exhorted him successfully and the Mongols attacked . Archbishop Ugrin was killed , but Kálmán and Béla managed to escape – though Kálmán ' s wounds were so serious that he died soon after . The Hungarians had lost nearly 30 , 000 men . Role of gunpowder and firearms . Several modern historians have speculated that Chinese firearms and gunpowder weapons were deployed by the Mongols at the Battle of Mohi . According to William H . McNeill , Chinese gunpowder weapons may have been used in Hungary at that time . Other sources mention weapons like " flaming arrows " and " naphtha bombs " . Professor Kenneth Warren Chase credits the Mongols with introducing gunpowder and its associated weaponry into Europe . Aftermath . After their victory , the Mongols regrouped and began a systematic assault on the Hungarian nation . The Hungarians ' losses were such that they were unable to mount an effective defence . An attempt was made to hold off the main Mongol army at the Danube , which was mostly successful , from April 1241 until January 1242 . In an unusually cold winter , the river froze over , and after a number of close battles , the Mongols managed to cross . The royal family escaped to Austria to seek help from their ally Duke Frederick , but instead he arrested them and extorted an enormous ransom in gold and forced the king to cede three western counties to Austria . It was at this point that King Béla and some of his retinue fled south - west , through Hungarian - controlled territory , to the Adriatic coast and the castle of Trogir , where they stayed until the Mongols retreated . While the king kept himself apprised of the situation in the rest of the country , he made numerous attempts to contact other rulers of Europe , including the Pope , the Holy Roman Emperor , and the King of France , but none seemed interested , and all seemed to have the same profound misunderstanding of the threat posed by the Mongol armies , which were by this time within a week ' s ride of the borders of France . The Mongols appointed a darughachi in Hungary and minted coins in the name of Khagan . According to Michael Prawdin , the lands of Béla were assigned to Orda by Batu as an appanage . Meanwhile , in the main territory of Hungary , surviving members of the royal retinue , being for the large part those that did not get to the battle of Mohi in time to participate , along with a number of unorganised irregulars consisting mostly of armed peasants , employed guerrilla tactics to harass the Mongol troops , occasionally engaging them in open battle . Much of the civilian population fled to areas of refuge inaccessible to the Mongol cavalry : high mountains in the north and east , swamps ( especially on the Puszta , around Székesfehérvár and in the west [ the Hanság ] ) , and older earthwork fortresses ( most of which were in a motte - and - bailey form or consisted of a mud - banked enclosure on the top of a mountain , steep natural hill or man - made hill ) . Rogerius recounts his experience in one such refuge called Fátra in his " Carmen Miserable " . ( Such places are often referred to by the German term " Fluchtburg " . ) At dawn on 11 December 1241 , Great Khan Ögedei died , causing the Mongols to retreat to Mongolia so that the princes of the blood could be present for the election of a new great khan . Prior to their departure , the Mongols were having difficulty pacifying the country , though they had planned to attack Austria and eventually Germany and Italy . While the defeat of the Hungarian army at the River Sajó is most often described in a couple of sentences as an effortless rout of the Hungarian army by the Mongols , this is an oversimplification . The Hungarian army as well as irregulars from the countryside proved dangerous foes and Mongol losses were significant . Subutai ' s engineers faced greater difficulties in constructing a bridge in the deeper - than - expected waters , and managed to attack the Hungarian rear just in time , as Batu ' s forces were being stretched and taxed by the numerically superior Hungarian forces . By the mid - 13th century , the Hungarian army is thought to have abandoned the tactics of the steppe nomads that made them such effective fighters against the German states , France , Italy , Spain , Poland , the Balkans and the Low Countries in the ninth and tenth centuries . But some historians have expressed doubts about this , and have suggested that the Hungarian military became more Westernised after the Mongol invasion and because of it ; further that using steppe tactics , early Hungary rebuffed German offensives many times ( in the wars of 1030 , 1031 , 1051 , 1053 and 1074 ) in the western borders of Hungary . Light horse archers had a less important military role after the Hungarians adopted Christianity . The majority of the horse archers were conscripted from various ethnic groups , such as Székelys , Kipchaks , Jassic people and ( after Mohi ) Cumans from the poorest peripheric regions of the kingdom ( southern parts , the middle of the Great Hungarian Plain and eastern parts of Transylvania ) . Nonetheless , during the battle , Batu Khan ' s personal guards were attacked and his life placed in peril . At another point , the Mongol troops were being routed by the Hungarian archers followed up by the heavy mounted knights , and only the personal rallying of Batu Khan prevented his army retreating . In spite of this , by Candlemas ( February ) 1242 , more than a year after the initial invasion and a few months before the Mongols ' withdrawal , a significant number of important castles and towns had resisted the formidable and infamous Mongol siege tactics . Among the nearly eighty sites that remained unconquered , only three were of the most formidable type : the then - new stone castle on an elevation : Fülek , Léka ( near the western border ) and Németújvár . The rest were either fortified towns ( e . g . , Székesfehérvár ) , old committal centre castles ( e . g . , Esztergom citadel ) , fortified monasteries ( e . g . Tihany and Pannonhalma ) or military fortresses ( e . g . Vécs guarding a main trade route in the mountains of Transylvania . Ultimately , the country was not subdued , and though much of the population was slaughtered , the king and higher nobility avoided capture . As a tardy revenge , the Hungarians and Croats ambushed and destroyed the rearguard division of the retreating Mongol army in the Carpathians . After the withdrawal of the Mongol troops , they were never again to return to Hungary with a force capable of laying siege to fortified cities , as the Chinese bombardiers and engineers under general Subutai were no longer deployed in the European theater of operations . Subutai was reassigned by Guyuk to engage the Southern Song , and died of old age in 1248 . Hungary lay in ruins . Nearly half of the inhabited places had been destroyed by the invading armies . Around 15 to 25 percent of the population was lost , mostly in lowland areas , especially in the Alföld ( where there were hardly any survivors ) , in the southern reaches of the Hungarian plain in the area now called the Banat , and in southern Transylvania . However , the power of the kingdom was not broken . Within a year of the withdrawal of the Mongols , the three westernmost counties ( Moson , Sopron , and Vas ) that were extorted as ransom by Duke Frederick of Austria were recaptured , and a local uprising in Slavonia was quashed . The threat of another Mongol invasion , this time taken seriously , was the source of exceptional national unity and provided the impetus for Béla IV ' s extensive expansion of Hungarian defences , especially the building of new stone castles ( forty - four in the first ten years ) and the revitalization of the army , including expanding the number of heavily armoured cavalry in the royal army . Béla IV is seen now as a second founder of the nation , partly in recognition of all that was done during his reign to reconstruct and fortify the country against foreign invasion from the east . These improvements were to pay off , in 1284 , when Nogai Khan attempted an invasion of the country . In that event , the invasion was defeated easily , as were a number of other minor attacks before and after . In the coming centuries , as the power of the Mongols of the Russian steppe waned and western defences became more capable , the attention of countries of central Europe would increasingly be directed to the south - east , and the growing power of the Ottoman Empire .