A cikin 1241-1242, Masarautar ta sami babban rauni a sakamakon mamayewar Mongol na Turai.Bayan da Mongols suka mamaye kasar Hungary a shekara ta 1241, sojojin kasar Hungary sun yi galaba a kai a yakin Mohi.Sarki Béla IV ya gudu daga fagen fama sannan kuma ƙasar bayan Mongols sun bi shi har zuwa iyakarta.Kafin Mongols su ja da baya, yawancin jama'a (20-50%) sun mutu.^[22] A cikin filayen, an lalata tsakanin 50 zuwa 80% na ƙauyukan.^[23] Sai dai ƙauyuka, birane masu ƙarfi da kuma abbeys ne kawai za su iya jure harin, saboda Mongols ba su da lokaci don dogon kewaye - burinsu shine ƙaura zuwa yamma da wuri-wuri.An bar injinan kewaye da injiniyoyinSinawa da Farisa waɗanda suka yi amfani da su don Mongols a cikin ƙasashen Kyivan Rus' da aka ci.^{[24 <]} > Barnar da mamayar Mongol ta yi daga baya ta kai ga gayyato mazauna wasu sassa na Turai, musamman daga Jamus.A lokacin yaƙin neman zaɓe na Mongols a kan Kievan Rus, an kori wasu ’yan Cuman 40,000, ’yan ƙabilar arna Kipchaks, zuwa yamma da tsaunin Carpathian.^[25] A can, Cumans sun yi kira ga Sarki Béla IV don kariya.^[26] Mutanen Jassic na Iran sun zo Hungary tare da Cumans bayan Mongols sun ci su.Cumans sun kasance watakila har zuwa 7-8% na yawan jama'ar Hungary a cikin rabin na biyu na karni na 13.^{[27 <>]} A cikin ƙarnuka da yawa sun kasance sun haɗa kai cikin al'ummar Hungary, kuma harshensu ya ɓace, amma sun kiyaye ainihin su da kuma 'yancin kai na yanki har zuwa 1876. ^[28.]Sakamakon mamayewar Mongol, Sarki Béla ya ba da umarnin gina ɗaruruwan katangar dutse da kagara don taimakawa wajen kare kai hari na biyu na Mongol.Mongols sun dawo Hungary a cikin 1286, amma sababbin tsarin gine-ginen dutse da sababbin dabarun soja da suka hada da mafi girma na manyan makamai sun dakatar da su.Sojojin Mongol da suka mamaye sun yi galaba a kusa da Pest daga rundunar sojojin sarki Ladislaus IV.Daga baya kuma an dakile harin da hannu.Gine-ginen da Béla IV ya gina sun kasance da amfani sosai a wani lokaci mai tsawo a gwagwarmayar da Daular Usmaniyya .Duk da haka, kuɗin gina su ya ba wa Sarkin Hungariya bashin ga manyan masu mallakar gidaje, ta yadda ikon sarauta da Béla IV ya kwato bayan mahaifinsa Andrew II ya raunana sosai ya sake tarwatse a cikin ƙananan mutane.