The son of Bela II – Geza II (1141–1162) also had to wage war with Boris Kolomanović. In 1151 this struggle ended in victory. Then the main problem for the Hungarian king was the conflict with Byzantium, where Boris Kolomanović moved to in the 1150s. Geza II, in turn, supported his cousin against the Byzantine Emperor Manuel I Andronicus Comnenus. In the end, Boris died in the war with the Hungarians, and in 1155 peace was concluded between Hungary and Byzantium. Then Geza II entered into an alliance with Germany, and in 1158 the Hungarian detachment took part in the siege of Milan by the troops of Frederick I Barbarossa.
After the death of Geza, first Laszlo II (1162–1163), and after his death – Istvan IV (1163) seized power. Both pleaded vassals of Byzantium. But in June 1163, Istvan III nevertheless occupied the throne with the support of the army of the German emperor Frederick I Barbarossa, and the Byzantine invasion of Hungary was repelled in the same year.
However, according to the will of Geza II, Croatia and Dalmatia were to come under the management of Bela, the youngest son of Geza. When Emperor Manuel realized that he could not recover the throne of Istvan IV, he demanded from his nephew Istvan III (1162-1172) in exchange for recognition to cede the border region of Seremsheg and take Bela hostage to Constantinople. As soon as Bela was in Byzantium, Manuel launched a war with Istvan III under the slogan of protecting Bela’s rights, and achieved that in 1167 where Croatia and Dalmatia were actually under the control of Byzantium. Bela, brought up at the court of Constantinople, became a true Byzantine in terms of language, habits and customs, even took the name Aleksey and probably converted to Orthodoxy. When Istvan III died in 1172, his younger brother easily established himself on the throne under the name of Bela III (1172-1196).
The new king was dissatisfied with the backwardness of Hungary in comparison with cultural Byzantium, therefore he strongly encouraged the development in the country of education, sent Hungarians to study in Italy, France, England; under him the kingdom flourished, the treasury was full, the royal power was greatly strengthened. After the death of Manuel in 1180, Bela III returned the lands of Croatia to Hungarian rule, and during a series of coups in Byzantium, he took the towns of Branichev and Belgrade from Byzantium. Then he married his daughter Margaret to the new emperor Isaac II and reconciled with the empire (1185). In 1188, the Hungarians conquered the Galician principality, taking advantage of the power struggle between the heirs of Yaroslav , but the excesses of the Hungarians led to the rebellion of the Galicians, and flight from Galich the son of the king -Endre (Andras), whom Bela III tried to make the Galician prince. However, in general, his power was great, Hungary had become one of the strongest feudal kingdoms in Europe.
After the death of Bela III, the war for the throne began again between his two sons: his younger brother Endre (Andrash) who spoke out against then King Emeric (1196-1204 ). Most Hungarians liked the more cheerful and frivolous Endre than those who obeyed Emeric’s priests. In 1197, Endre defeated the king’s forces and forced his brother to give up Croatia and Dalmatia. But in 1199 Emeric defeated him and forced him to flee to Austria under the protection of Babenberg. The brothers agreed to recognize each other’s heirs. In 1201 Emeric subjugated Serbia, in 1202–1203 fought with Bulgaria, eventually proclaimed himself king of Serbia and Bulgaria, but in a war with Bulgarian king Kaloyan he suffered a defeat. In 1204, the war for the throne resumed. Emeric stopped the war with a bold act: he went alone to his brother’s camp and demanded that he surrender. Struck by Endre, he did not dare to resist and allowed the king to lead himself to prison. Then the brothers reconciled again, but soon Emeric died suddenly. Andre became the guardian of his young son Laslo III (1204-1205) and quickly seized all power. Emeric’s widow, Constance of Aragon, fled to Vienna, but here Laszlo III died suddenly from an illness.
The king was now Endre II, nicknamed the Crusader (1205-1235). He generously distributed the royal lands to his supporters and pursued an adventurous foreign policy; the central power under him quickly weakened. For many years, Endre II sent troops to the Carpathians, and to the Galicia-Volyn principality, which was torn apart by a fierce struggle between the applicants after the death of the powerful prince Roman Mstyslavych (1205). Andre even proclaimed himself “king of Galicia and Lodomeria”. However, all trips in the end were unsuccessful. While Endre was wasting his strength in the struggle for Galich, Hungary was ruled by his wife, Queen Gertrude of Meran. She distributed land to her favorites, who committed various kinds of crimes with impunity; in the end, the disgruntled grandees plotted and brutally murdered the queen (1213), with André punishing only the head of the conspirators, forgiving the others, which angered his son and heir Bela . Endre chose to go to Palestine, becoming the head of the Fifth Crusade (1217-1221). The actions of the Hungarians in Palestine were generally unsuccessful, after several raids on Muslim territory, André returned to Hungary, giving Asenyam the controversial Hungarian cities across Bulgaria.
In the absence of the king, Hungary finally fell into a state of anarchy, the feudal lords almost got out of submission, the treasury was plundered. The younger son of Endre II, Kalman (Koloman) in 1219 was expelled from Galich by Mstislav Udatny. Finally, in 1222, Endre was forced to sign the Golden Bull, the equivalent of the Magna Carta, published in England seven years earlier. The Golden Bull guaranteed the rights mainly of the upper classes and clergy and officially allowed the feudal lords to oppose the king if their rights were infringed.
Endre II tried to rely on the knights of the Teutonic Order, who gave them a place to settle in Bartsasag (in Transylvania), but after a few years he expelled them from the kingdom, and in 1226 they moved to the Baltic States. Meanwhile, the son and heir of Endre II, Bela, appointed to govern Croatia and Dalmatia, began to take land there from the masterful magnates. He dismissed Bela and appointed Kalman in his place, and placed him in Transylvania instead. The eldest son, Bela IV (1235–1270) , succeeded the king in 1235. The latter managed to restore the Hungarian kingdom after the Mongol invasion, but under his grandson Laszlo IV the kingdom itself plunged into a period of fragmentation and feudal anarchy. Moreover, in 1301, in connection with the death of Andrash III, the Arpad dynasty was suppressed and the throne of Hungary became empty.