The Kingdom of Croatia (; ; ), also known with full diplomatic name Kingdom of Croatia and Dalmatia (), entered a personal union with the Kingdom of Hungary in 1102, after a period of rule of kings from the Trpimirović and Svetoslavić dynasties and a succession crisis following the death of king Demetrius Zvonimir.

With the coronation of King Coloman of Hungary as "King of Croatia and Dalmatia" in 1102 in Biograd, the realm passed to the Árpád dynasty until 1301, when the (male) line of the dynasty died out. Then, kings from the Capetian House of Anjou, who were also cognatic descendants of the Árpád kings, ruled the kingdoms. Later centuries were characterized by conflicts with the Mongols, who sacked Zagreb in 1242, competition with Venice for control over Dalmatian coastal cities, and internal warfare among Croatian nobility. Various individuals emerged during the period, such as Paul I Šubić of Bribir, who was representing the most powerful Croatian dynasty at the time, the Šubić noble family. These powerful individuals were on occasion able to de facto secure great deal of independence for their fiefdoms. The Ottoman incursion into Europe in the 16th century significantly reduced Croatian territories and left the country weak and divided. After the death of Louis II in 1526 during the Battle of Mohács and a brief period of dynastic dispute, both crowns passed to the Austrian House of Habsburg, and the realms became part of the Habsburg monarchy.

Some of the terms of Coloman's coronation and the later status of the Croatian nobles are detailed in the Pacta Conventa, a document preserved only in transcript from the 14th century. The precise terms of this relationship became a matter of dispute in the 19th century; nonetheless, even in dynastic union with Hungary, institutions of separate Croatian statehood were maintained through the Sabor (an assembly of Croatian nobles) and the Ban (viceroy). In addition, the Croatian nobles retained their lands and titles.

Name The diplomatic name of the kingdom was "Kingdom of Croatia and Dalmatia" () until 1359 when a plural form "kingdoms" () came into use.Lujo Margetić: Hrvatska i Crkva u srednjem vijeku, Pravnopovijesne i povijesne studije, Rijeka, 2000, p. 91Ferdo Šišić: Povijest Hrvata u vrijeme narodnih vladara, p. 523 The change was a consequence of the victory of Louis I against the Republic of Venice and the Treaty of Zadar, by which the Venetian Republic lost its influence over Dalmatian coastal cities. However, the kingdom was still mostly referred to as the Kingdom of Croatia and Dalmatia until Venice regained the Dalmatian coast in 1409. A common synonym were "Sclavonia" (Slavonija and Slovinje) and "tota Sclauonia" (Whole Slavonia). The most common Croatian language form of the name was Hrvatska zemlja ("Croatian country" or "Croatian land").Dragomir Džoić: Federalističke teorije i hrvatska država, 1998, p. 75Ferdo Šišić: Geschichte der Kroaten, 1917, p. 385

Background

Succession crisis

Demetrius Zvonimir was the King of Croatia of the Svetoslavić branch of the House of Trpimirović. He began as a Ban of Croatia in the service of Peter Krešimir IV. Peter probably declared him his heir and, in 1075, Demetrius Zvonimir succeeded to the Croatian throne. Zvonimir married Helen of Hungary from the Árpád dynasty in 1063. Helen was a Hungarian princess, daughter of Béla I, and sister to King Ladislaus I of Hungary. They had a son, Radovan, who died in his late teens or early twenties. After Zvonimir's death in 1089, he was succeeded by Stephen II, last of the House of Trpimirović. Stephen's rule was relatively ineffectual and lasted less than two years. He spent most of this time in the tranquility of the monastery of St. Stephen beneath the Pines () near Split. Stephen II died peacefully at the beginning of 1091, without leaving an heir. Since there was no living male member of the House of Trpimirović, civil war and unrest broke out in Croatia shortly afterward.Neven Budak – Prva stoljeća Hrvatske, Zagreb, 1994. p. 77

The widow of late King Zvonimir, Helen, tried to keep her power in Croatia during the succession crisis.Neven Budak – Prva stoljeća Hrvatske, Zagreb, 1994. p. 80 (in Croatian) Some Croatian nobles around Helen, possibly the Gusić familyNada Klaić: Povijest Hrvata u ranom srednjem vijeku, II Izdanje, Zagreb 1975. p. 492 (in Croatian) and/or Viniha from Lapčan family, contesting the succession after the death of Zvonimir, asked King Ladislaus I to help Helen and offered him the Croatian throne, which was seen as rightfully his by inheritance rights. According to some sources, several Dalmatian cities also asked King Ladislaus for assistance, and Petar Gusić with Petar de genere Cacautonem presented themselves as "White Croats" (Creates Albi), on his court. Thus the campaign launched by Ladislaus was not purely a foreign aggressionBárány, Attila (2012). "The Expansion of the Kingdom of Hungary in the Middle Ages (1000–1490)". In Berend, Nóra. The Expansion of Central Europe in the Middle Ages. Ashgate Variorum. pp. 344–345 nor did he appear on the Croatian throne as a conqueror, but rather as a successor by hereditary rights.Márta Font - Ugarsko Kraljevstvo i Hrvatska u srednjem vijeku (Hungarian Kingdom and Croatia in the Middlea Ages) , pp. 8–9 In 1091 Ladislaus crossed the Drava river and conquered the entire province of Slavonia without encountering opposition, but his campaign was halted near the Iron Mountains (Mount Gvozd).Archdeacon Thomas of Split: History of the Bishops of Salona and Split (ch. 17.), p. 93. Since the Croatian nobles were divided, Ladislaus had success in his campaign, yet he was not able to establish his control over entire Croatia, although the exact extent of his conquest is not known. At this time the Kingdom of Hungary was attacked by the Cumans, who were likely sent by Byzantium, so Ladislaus was forced to retreat from his campaign in Croatia. Ladislaus appointed his nephew Prince Álmos to administer the controlled area of Croatia, established the Diocese of Zagreb as a symbol of his new authority and went back to Hungary. In the midst of the war, Petar Snačić was elected king by Croatian feudal lords in 1093. Petar's seat of power was based in Knin. His rule was marked by a struggle for control of the country with Álmos, who was not able to establish his rule and was forced to withdraw to Hungary in 1095.Nada Klaić: Povijest Hrvata u ranom srednjem vijeku, II Izdanje, Zagreb 1975. pp. 508–509 (in Croatian)

Ladislaus died in 1095, leaving his nephew Coloman to continue the campaign. Coloman, as was the case with Ladislaus before him, was not seen as a conqueror but rather as a pretender to the Croatian throne. Coloman assembled a large army to press his claim on the throne and in 1097 defeated King Petar's troops in the Battle of Gvozd Mountain, who was killed in battle. Since the Croatians did not have a leader any more and Dalmatia had numerous fortified towns that would be difficult to defeat, negotiations started between Coloman and the Croatian feudal lords. It took several more years before the Croatian nobility recognised Coloman as the king. Coloman was crowned in Biograd in 1102 and the title now claimed by Coloman was "King of Hungary, Dalmatia, and Croatia". Some of the terms of his coronation are summarized in Pacta Conventa by which the representatives of the noble institution of twelve noble tribes of Croatia agreed to recognise Coloman as king. In return, the 12 Croatian nobles that signed the agreement retained their lands and properties and were granted exemption from tax or tributes. The nobles were to send at least ten armed horsemen each beyond the Drava River at the kings expense if his borders were attacked.Trpimir Macan: Povijest hrvatskog naroda, 1971, p. 71 (full text of Pacta conventa in Croatian)Ferdo Šišić: Priručnik izvora hrvatske historije, Dio 1, čest 1, do god. 1107. Zagreb 1914., p. 527–528 (full text of Pacta conventa in Latin) Despite that Pacta Conventa is not an authentic document from 1102, there was almost certainly some kind of contract or agreement between the Croatian nobles and Coloman which regulated the relations in the same way.Neven Budak – Prva stoljeća Hrvatske, Zagreb, 1994. p. 39 (in Croatian)

Historical and legal context

In 1102, after a succession crisis, the crown passed into the hands of the Árpád dynasty, with the crowning of King Coloman of Hungary as "King of Croatia and Dalmatia" in Biograd. The precise terms of the union between the two realms became a matter of dispute in the 19th century. The two kingdoms were united under the Árpád dynasty either by the choice of the Croatian nobility or by Hungarian force. Croatian historians hold that the union was a personal one in the form of a shared king, a view also accepted by a number of Hungarian historians,Kristó Gyula: A magyar–horvát perszonálunió kialakulása [The formation of Croatian-Hungarian personal union](in Hungarian)Márta Font – Ugarsko Kraljevstvo i Hrvatska u srednjem vijeku [Hungarian Kingdom and Croatia in the Middlea Ages] "Medieval Hungary and Croatia were, in terms of public international law, allied by means of personal union created in the late 11th century."Lukács István - A horvát irodalom története, Budapest, Nemzeti Tankönyvkiadó, 1996.[The history of Croatian literature] (in Hungarian)Barna Mezey: Magyar alkotmánytörténet, Budapest, 1995, p. 66 while Serbian and Hungarian nationalist historians preferred to see it as a form of annexation. The claim of a Hungarian occupation was made in the 19th century during the Hungarian national reawakening. Thus in older Hungarian historiography Coloman's coronation in Biograd was a subject of dispute and their stance was that Croatia was conquered. Although claims of this kind can also be found today, since the Croatian-Hungarian tensions are gone, it has generally been accepted that Coloman was crowned in Biograd for king. Today, Hungarian legal historians hold that the relationship of Hungary with the area of Croatia and Dalmatia in the period till 1526 and the death of Louis II was most similar to a personal union, resembling the relationship of Scotland to England.Banai Miklós, Lukács Béla: Attempts for closing up by long range regulators in the Carpathian Basin

According to the Worldmark Encyclopedia of Nations and the Grand Larousse encyclopédique, Croatia entered a personal union with Hungary in 1102, which remained the basis of the Hungarian-Croatian relationship until 1918, while Encyclopædia Britannica specified the union as a dynastic one. According to the research of the Library of Congress, Coloman crushed opposition after the death of Ladislaus I and won the crown of Dalmatia and Croatia in 1102, thus forging a link between the Croatian and Hungarian crowns that lasted until the end of World War I. Hungarian culture permeated northern Croatia, the Croatian-Hungarian border shifted often, and at times Hungary treated Croatia as a vassal state. Croatia had its own local governor, or Ban; a privileged landowning nobility; and an assembly of nobles, the Sabor. According to some historians, Croatia became part of Hungary in the late 11th and early 12th century, yet the actual nature of the relationship is difficult to define. Sometimes Croatia acted as an independent agent and at other times as a vassal of Hungary. However, Croatia retained a large degree of internal independence. The degree of Croatian autonomy fluctuated throughout the centuries as did its borders.Singleton, p. 29