Croatia in personal union with Hungary in the context of "Battle of Mohács"

Croatia, officially the Republic of Croatia, is a country in Central and Southeast Europe, on the coast of the Adriatic Sea. It borders Slovenia to the northwest, Hungary to the northeast, Serbia to the east, Bosnia and Herzegovina and Montenegro to the southeast, and shares a maritime border with Italy to the west. Its capital and largest city, Zagreb, forms one of the country's primary subdivisions, with twenty counties. Other major urban centers include Split, Rijeka and Osijek. The country spans 56,594 square kilometres (21,851 square miles), and has a population of nearly 3.9 million.

The Croats arrived in modern-day Croatia, then part of Roman Illyria, in the late 6th century. In the 7th century, they organized the territory into two duchies. Croatia was first internationally recognized as independent on 7 June 879 during the reign of Duke Branimir. Tomislav became the first king by 925, elevating Croatia to the status of a kingdom. During the succession crisis after the Trpimirović dynasty ended, Croatia entered a personal union with Hungary in 1102. In 1527, faced with Ottoman conquest, the Croatian Parliament elected Ferdinand I of Austria to the Croatian throne. In October 1918, the State of Slovenes, Croats, and Serbs, independent from the Habsburg Empire, was proclaimed in Zagreb, and in December 1918, it merged into the Kingdom of Yugoslavia. Following the Axis invasion of Yugoslavia in April 1941, most of Croatia was incorporated into a Nazi-installed puppet state, the Independent State of Croatia. A resistance movement led to the creation of the Socialist Republic of Croatia, which after the war became a founding member and constituent of the Socialist Federal Republic of Yugoslavia. On 25 June 1991, Croatia declared independence, and the War of Independence was successfully fought over the next four years.

From the 1220s to the 1240s, the Mongols conquered the Turkic states of Volga Bulgaria, Cumania and Iranian state of Alania, and various principalities in Eastern Europe. Following this, they began their invasion into Central Europe by launching a two-pronged invasion of then-fragmented Poland, culminating in the Battle of Legnica (9 April 1241), and the Kingdom of Hungary, culminating in the Battle of Mohi (11 April 1241). Invasions were also launched into the Caucasus against the Kingdom of Georgia, the Chechens, the Ingush, and Circassia though they failed to fully subjugate the latter. More invasions were launched in Southeast Europe against Bulgaria, Croatia, and the Latin Empire. The operations were planned by General Subutai (1175–1248) and commanded by Batu Khan (c. 1207–1255) and Kadan (d. c. 1261), two grandsons of Genghis Khan. Their conquests integrated much of Eastern European territory into the empire of the Golden Horde. Warring European princes realized they had to cooperate in the face of a Mongol invasion, so local wars and conflicts were suspended in parts of central Europe, only to be resumed after the Mongols had withdrawn. After the initial invasions, subsequent raids and punitive expeditions continued into the late 13th century.

Melik, one of the princes from the Ögedei family who participated in the expedition, invaded the Transylvania region of the Hungarian kingdom, called Sasutsi in sources.

The Croats of Bosnia and Herzegovina (Croatian: Hrvati Bosne i Hercegovine), often referred to as Bosnian Croats (bosanski Hrvati) or Herzegovinian Croats (hercegovački Hrvati), are native to Bosnia and Herzegovina and constitute the third most populous ethnic group, after Bosniaks and Serbs. They are one of the three constitutive nations of Bosnia and Herzegovina. Croats of Bosnia and Herzegovina have made significant contributions to the culture of Bosnia and Herzegovina. Most Croats identify themselves as Catholics and speak Croatian language.

Croats have been present in Bosnia and Herzegovina since the Slavic migrations to the Balkans. The Kingdom of Croatia under native rulers and later in personal union with Hungary encompassed large parts of Bosnia and Herzegovina in the west until the 16th century. The Croats also lived under the Kingdom of Bosnia until it fell to the Ottoman Empire in the second half of the 15th century. Between the 15th and 19th centuries, Catholics in Ottoman Bosnia and Herzegovina were often persecuted by the Ottomans, prompting many to flee the area, especially during the Great Turkish War and the Morean War in the second half of the 17th century, when their numbers were reduced to 30,000. At the end of the 17th century and in the early 18th century, the number of Catholics began to increase, with many of those who had fled returning. In the second half of the 19th century, especially during the Austro-Hungarian rule in Bosnia and Herzegovina, the Croats became active political subjects, participating in Croatian national revival. The 20th century brought political turmoil, and poor economic conditions led to increased emigration. Ethnic cleansing within Bosnia and Herzegovina in the 1990s saw Croats forced to go to different parts of Bosnia and Herzegovina, despite having lived in numerous regions before the Bosnian War. The 2013 population census in Bosnia and Herzegovina recorded 544,780 residents registering as of Croat ethnicity.

The counties of Croatia (Croatian: hrvatske županije) are the first-level administrative subdivisions of the Republic of Croatia. Since they were re-established in 1992, Croatia has been divided into 20 counties and the capital city of Zagreb, which has the authority and legal status of both a county and a city (separate from the surrounding Zagreb County). As of 2015, the counties are subdivided into 128 cities and 428 (mostly rural) municipalities. The divisions have changed over time since the medieval Croatian state. They reflected territorial losses and expansions; changes in the political status of Dalmatia, Dubrovnik and Istria; and political circumstances, including the personal union and subsequent development of relations between the Kingdom of Croatia-Slavonia and the Kingdom of Hungary.

Split (/splɪt/; Croatian: [splît] , see other names) is the second-largest city of Croatia after the capital Zagreb. It is the largest city in Dalmatia, largest city on the Croatian coast, and the seat of the Split-Dalmatia County. The Split metropolitan area is home to about 330,000 people. It lies on the eastern shore of the Adriatic Sea and is spread over a central peninsula and its surroundings. An intraregional transport hub and popular tourist destination, the city is linked to the Adriatic islands and the Apennine Peninsula. More than 1 million tourists visit it each year.

The city was founded as the Greek colony of Aspálathos (Ancient Greek: Ἀσπάλαθος) in the 3rd or 2nd century BCE on the coast of the Illyrian Dalmatae, and in 305 CE, it became the site of the Palace of the Roman emperor Diocletian. It became a prominent settlement around 650 when it succeeded the ancient capital of the Roman province of Dalmatia, Salona. After the sack of Salona by the Avars and Slavs, the fortified Palace of Diocletian was settled by Roman refugees. Split became a Byzantine city. Later it drifted into the sphere of the Republic of Venice and the Kingdom of Croatia. For much of the High and Late Middle Ages, Split enjoyed autonomy as a free city of the Dalmatian city-states, caught in the middle of a struggle between Venice and Croatia for control over the Dalmatian cities.

The Hundred Years' Croatian–Ottoman War (Croatian: Stogodišnji hrvatsko-turski rat, Stogodišnji rat protiv Turaka, Stogodišnji rat s Osmanlijama) was a sequence of conflicts, mostly of relatively low intensity ("Small War", Croatian: Mali rat), between the Ottoman Empire and the medieval Kingdom of Croatia (ruled by the Jagiellon and Zápolya dynasties), and the later Habsburg Kingdom of Croatia. Besides periods of small-scale borderland warfare, the conflict also saw episodes of major conquest campaigns of Croatian land which was undertaken by the Ottomans especially during the 16th century.

The expansion of the Ottoman Empire in Europe was stopped in the Battle of Sisak 1593. Nevertheless, the Ottoman Empire held control over parts of Croatia from the 16th to the end of the 17th century, when most of the territories were regained in the Great Turkish War, except for lands known as Turkish Croatia (roughly corresponding to modern day western Bosnia and Herzegovina) which remained in Ottoman hands until the 19th century.

The siege of Zara or siege of Zadar (Croatian: opsada Zadra; Hungarian: Zára ostroma; 10–24 November 1202) was the first major action of the Fourth Crusade and the first attack against a Catholic city by Catholic crusaders. The crusaders had an agreement with Venice for transport across the sea, but the price far exceeded what they were able to pay. Venice set the condition that the crusaders help them capture Zadar (or Zara), a constant battleground between Venice on one side and the Kingdom of Croatia and Dalmatia (Sclavonia) and Hungary on the other, whose king, Emeric, pledged himself to join the Crusade. Although some of the crusaders refused to take part in the siege, the attack on Zadar began in November 1202 despite letters from Pope Innocent III forbidding such an action and threatening excommunication. Zadar fell on 24 November and the Venetians and the crusaders sacked the city. After wintering in Zadar, the Fourth Crusade continued its campaign, which led to the siege of Constantinople.

This is a complete list of dukes and kings of Croatia (Croatian: knez, kralj) under domestic ethnic and elected dynasties during the Duchy of Croatia (until 925), the Kingdom of Croatia (925–1102), the Kingdom of Croatia and Dalmatia (1102–1526 in union with Kingdom of Hungary, 1527–1868 under Habsburg dynasty ending with 1868–1918 Kingdom of Croatia-Slavonia).

This article follows the monarch's title number according to Hungarian succession for convenience. For example, the Hungarian monarch Béla IV is according to Croatian succession correctly titled Béla III. This is because Hungarians had a king named Béla prior to the incorporation of Croatia under the Hungarian Crown but the Croats did not.

A Byzantine–Hungarian War was fought between Byzantine and Hungarian forces in the Balkans from 1180 to 1185. Taking advantage of the internal conflicts in the Byzantine Empire after Emperor Manuel's death, Béla III of Hungary reoccupied Croatia, Dalmatia and Syrmia, restoring Hungarian suzerainty over these territories after fourteen years.