|son of:||Andrew II|
|periods of reign:||1235-1270|
|children:||Kunigunda, Margaret, Catherine, Anna, Yolanda, Elisabeth, Constance, Stephen, Margaret, Béla|
Béla IV was considered to be one of the most significant monarchs of the Árpád Dynasty. He is also referred to as second founder of the state, because of his efforts to rebuild his devastated country after the Mongol invasion. With his first measures as the new king, Béla made it clear that he would stop his father’s policy of lifetime grants, in every way. He took back the donations, and helped the pagan and nomad Cumans settle down in the country. All these actions decreased significantly his popularity, already in the first years of his reign.
In 1240 dreadful Mongol armies reached the Eastern border of the country. Hungary was not prepared enough for the Mongols attacking from three sides in 1241. Although Béla’s army of 80 000 soldiers, mainly mercenaries, defeated the attack, it was virtually annihilated in a battle of Mohi due to a poorly chosen army campsite. The king fled first to Pressburg (Bratislava, Slovakia), and later to the castle of Trau by the Adriatic See. The Mongols conquered Transylvania, Transdanubia and Pest. In spring 1242 they unexpectedly pulled back, leaving a fully devastated country behind.
Due to the consequences of the Mongol invasion, the returning king realized the mistakes of his former policy. Afterwards he endeavoured to reach consolidation, instead of confrontation. He was focusing on taking measures to prevent a new possible Mongol attack. He had modern castles built from stone, and encouraged his dependants to do so by giving them estates. The king was a forerunner of castle construction: around 1250 he had the castle of Visegrád built, and he also established the castle in Buda. To replace the loss of at least 15 percent of the population, who perished during the Mongol invasion, the king invited foreign colonists to settle down in Hungary. Béla IV granted privileges to the cities, and at the same time, put more emphasis on collecting taxes and duties. Minting coins of good quality resulted in the boosting of trade during his reign.
After 1250 he tried to conquer Austria, but after a period of battles, alliances and peace treaties he was forced to give up. In the last years of his life, he was mainly fighting against his own son. Because of the anarchical period following his death, his successors honoured Béla IV as the great king of peace.