Andrew II of Hungary in the context of "Béla III of Hungary"

Boril (Bulgarian: Борил) was the emperor (tsar) of Bulgaria from 1207 to 1218. He was the son of an unnamed sister of his predecessor, Kaloyan and Kaloyan's brothers, Peter II and Ivan Asen I, who had restored the independent Bulgarian state. After Kaloyan died unexpectedly in October 1207, Boril married his widow, a Cuman princess and seized the throne. His cousin, Ivan Asen, fled from Bulgaria, enabling Boril to strengthen his position. His other kinsmen, Strez and Alexius Slav, refused to acknowledge him as the lawful monarch. Strez took possession of the land between the Struma and Vardar rivers with the support of Stefan Nemanjić of Serbia. Alexius Slav secured his rule in the Rhodope Mountains with the assistance of Henry, the Latin Emperor of Constantinople.

Boril launched unsuccessful military campaigns against the Latin Empire and the Kingdom of Thessalonica during the first years of his reign. He convoked the synod of the Bulgarian Church in early 1211. At the assembly, the bishops condemned the Bogomils for heresy. After an uprising broke out against him in Vidin between 1211 and 1214, he sought the assistance of Andrew II of Hungary, who sent reinforcements to suppress the rebellion. He made peace with the Latin Empire in late 1213 or early 1214. After Henry died in 1216 and Andrew II left Hungary for a crusade, Ivan Asen returned to Bulgaria. He captured and blinded Boril in Tarnovo in 1218.

The high medieval Kingdom of Hungary was a regional power in central Europe. It came into existence in Central Europe when Stephen I, Grand Prince of the Hungarians, was crowned king in 1000 or 1001. He reinforced central authority and forced his subjects to accept Christianity. Although all written sources emphasize only the role played by German and Italian knights and clerics in the process, a significant part of the Hungarian vocabulary for agriculture and religion was taken from Slavic languages. Civil wars and pagan uprisings, along with attempts by the Holy Roman emperors to expand their authority over Hungary, jeopardized the new monarchy. The monarchy stabilized during the reigns of Ladislaus I (1077–1095) and Coloman (1095–1116). These rulers occupied Croatia and Dalmatia with the support of a part of the local population. Both realms retained their autonomous position. The successors of Ladislaus and Coloman—especially Béla II (1131–1141), Béla III (1176–1196), Andrew II (1205–1235), and Béla IV (1235–1270)—continued this policy of expansion towards the Balkan Peninsula and the lands east of the Carpathian Mountains, transforming their kingdom into one of the major powers of medieval Europe.

Rich in uncultivated lands, silver, gold, and salt deposits, Hungary became the preferred destination of mainly German, Italian, and French colonists. These immigrants were mostly peasants who settled in villages, but some were craftsmen and merchants, who established most of the cities of the Kingdom. Their arrival played a key role in the shaping of an urban lifestyle, habits, and culture in medieval Hungary. The location of the kingdom at the crossroads of international trade routes favored the coexistence of several cultures. Romanesque, Gothic, and Renaissance buildings and literary works written in Latin prove the predominantly Roman Catholic character of the culture; but Orthodox, and even non-Christian ethnic minority communities also existed. Latin was the language of legislation, administration and the judiciary, but "linguistic pluralism" contributed to the survival of many tongues, including a great variety of Slavic dialects.

The Fifth Crusade (September 1217 – August 29, 1221) was a campaign in a series of Crusades by Western Europeans to reacquire Jerusalem and the rest of the Holy Land by first conquering Egypt, ruled by the powerful Ayyubid sultanate, led by al-Adil, brother of Saladin.

After the failure of the Fourth Crusade, Innocent III again called for a crusade, and began organizing Crusading armies led by Andrew II of Hungary and Leopold VI of Austria, soon to be joined by John of Brienne, titular King of Jerusalem. An initial campaign in late 1217 in Syria was inconclusive, and Andrew departed. A German army led by cleric Oliver of Paderborn, and a mixed army of Dutch, Flemish and Frisian soldiers led by William I of Holland, then joined the Crusade in Acre, with a goal of first conquering Egypt, viewed as the key to Jerusalem. There, cardinal Pelagius Galvani arrived as papal legate and de facto leader of the Crusade, supported by John of Brienne and the masters of the Templars, Hospitallers and Teutonic Knights. Holy Roman Emperor Frederick II, who had taken the cross in 1215, did not participate as promised.

Béla IV (1206 – 3 May 1270) was King of Hungary and Croatia between 1235 and 1270, and Duke of Styria from 1254 to 1258. As the oldest son of King Andrew II, he was crowned upon the initiative of a group of influential noblemen in his father's lifetime in 1214. His father, who strongly opposed Béla's coronation, refused to give him a province to rule until 1220. In this year, Béla was appointed Duke of Slavonia, also with jurisdiction in Croatia and Dalmatia. Around the same time, Béla married Maria, a daughter of Theodore I Laskaris, Emperor of Nicaea. From 1226, he governed Transylvania as duke. He supported Christian missions among the pagan Cumans who dwelled in the plains to the east of his province. Some Cuman chieftains acknowledged his suzerainty and he adopted the title of King of Cumania in 1233. King Andrew died on 21 September 1235 and Béla succeeded him. He attempted to restore royal authority, which had diminished under his father. For this purpose, he revised his predecessors' land grants and reclaimed former royal estates, causing discontent among the noblemen and the prelates.

The Mongols invaded Hungary and annihilated Béla's army in the Battle of Mohi on 11 April 1241. He escaped from the battlefield, but a Mongol detachment chased him from town to town as far as Trogir on the coast of the Adriatic Sea. Although he survived the invasion, the Mongols devastated the country before their unexpected withdrawal in March 1242. Béla introduced radical reforms in order to prepare his kingdom for a second Mongol invasion. He allowed the barons and the prelates to erect stone fortresses and to set up their private armed forces. He promoted the development of fortified towns. During his reign, thousands of colonists arrived from the Holy Roman Empire, Poland and other neighboring regions to settle in the depopulated lands. Béla's efforts to rebuild his devastated country won him the epithet of "second founder of the state" (Hungarian: második honalapító).

Andrew III the Venetian (Hungarian: III. Velencei András, Croatian: Andrija III. Mlečanin, Slovak: Ondrej III., Italian: Andrea III il veneziano; c. 1265 – 14 January 1301) was King of Hungary and Croatia between 1290 and 1301. His father, Stephen the Posthumous, was the posthumous son of Andrew II of Hungary although Stephen's older half brothers considered him a bastard. Andrew grew up in Venice, and first arrived in Hungary upon the invitation of a rebellious baron, Ivan Kőszegi, in 1278. Kőszegi tried to play Andrew off against Ladislaus IV of Hungary, but the conspiracy collapsed and Andrew returned to Venice.

Being the last male member of the House of Árpád, Andrew was elected king after the death of King Ladislaus IV in 1290. He was the first Hungarian monarch to issue a coronation diploma confirming the privileges of the noblemen and the clergy. At least three pretenders—Albert of Austria, Mary of Hungary, and an adventurer—challenged his claim to the throne. Andrew expelled the adventurer from Hungary and forced Albert of Austria to conclude a peace within a year, but Mary of Hungary and her descendants did not renounce their claim. The Hungarian bishops and Andrew's maternal family from Venice were his principal supporters, but the leading Croatian and Slavonian lords were opposed to his rule.

James II (Catalan: Jaume) (31 May 1243 – 29 May 1311) was King of Majorca and Lord of Montpellier from 1276 until his death. He was the second son of James I of Aragon and his wife, Violant, daughter of Andrew II of Hungary. In 1279, by the Treaty of Perpignan, he became a vassal of the Crown of Aragon.

Pope Honorius III (c. 1150 – 18 March 1227), born Cencio Savelli, was head of the Catholic Church and ruler of the Papal States from 18 July 1216 to his death. A canon at the Basilica di Santa Maria Maggiore, he came to hold a number of important administrative positions, including that of Camerlengo. In 1197, he became tutor to the young Frederick II. As pope, he worked to promote the Fifth Crusade, which had been planned under his predecessor, Innocent III. Honorius repeatedly exhorted King Andrew II of Hungary and Emperor Frederick II to fulfill their vows to participate. He also gave approval to the recently formed Dominican and Franciscan religious orders.

The Roman Catholic Diocese of Cumania was a Latin-rite bishopric west of the Siret River (in present-day Romania) from 1228 to 1241. The lands incorporated into the diocese had been dominated by the nomadic Cumans since about 1100. Catholic missions began after Andrew II of Hungary granted Burzenland to the Teutonic Knights in 1211. After Andrew expelled the Knights from the territory in 1225, Dominican friars continued the Cuman mission. Robert, Archbishop of Esztergom baptized Boricius, an influential Cuman chieftain, two years later.

Robert ordained a Hungarian Dominican friar, Theodoric, as the first bishop of Cumania in early 1228. Pope Gregory IX confirmed Theodoric's consecration on 21 March of that year, and the diocese was subordinate to the Holy See in 1229. The episcopal see was on the Milcov River, but its exact location is unknown. The diocese included Burzenland and lands east of the Carpathian Mountains. Vlachs (Romanians) who belonged to the Orthodox Church were a significant part of the diocese's population. They did not follow the Catholic bishop, and persuaded many Catholic Hungarians and Saxons to accept their Orthodox bishops.