The official entering of Croatia into personal union with Hungary, becoming part of the Kingdom of Hungary, had several important consequences.

The country was ruled by a ban in the name of the king, elevating that previously existing rank to a position of highest importance in Croatia. A single ban governed all Croatian provinces until 1225, when the authority was split between one ban of The Whole of Slavonia and one ban of Dalmatia and Croatia. The positions were intermittently held by the same person after 1345, and officially merged back into one by 1476.

The Hungarian king also introduced a variant of the feudal system. Large fiefs were granted to individuals who would defend them against outside incursions thereby creating a system for the defence of the entire state. However, by enabling the nobility to seize more and more economic and military power, the kingdom itself lost influence to the Frankopan, Šubić, Nelipčić, Kačić, Kurjaković, Drašković, Babonić and other families.

The later kings sought to restore their influence by giving certain privileges to the towns, making them Royal Boroughs or Free Royal Towns (similar to the Free Cities in the Holy Roman Empire), which the kings defended from the feudal lords in return for the town's support.

The princes of Bribir from the Šubić family became particularly influential during the time of Pavao Šubić (1272-1312) who asserted control over large parts of Dalmatia, Slavonia and Bosnia during an internal conflict between the Árpád and Anjou ruling dynasties. Later, however, the Anjouvines intervened and scattered the Šubić family across the country (an important offspring being the Zrinski family), and later even selling the whole of Dalmatia to the Republic of Venice in 1409.

Ban Petar Berislavić,
"defendor Croatiae"

As the Turkish incursion into Europe started, Croatia was once again a border area between two major forces in this part of the world. While Croats under fra Ivan Kapistran contributed to the Christian victory over the Ottomans in the siege of Belgrade of 1456, they suffered a major defeat in the Battle of Krbava Field (in Lika, Croatia) in 1493 and gradually lost increasing amounts of territory to the Ottoman Empire.

Pope Leo X called Croatia the forefront of Christianity in 1519, given that several Croatian soldiers made significant contributions to the struggle against the Turks. Among them there were ban Petar Berislavić who won a victory at Dubica on the Una river in 1513, the captain of Senj Petar Kružić who defended the Klis fortress for 15 years, captain Nikola Jurišić who deterred by a magnitude larger Turkish force on their way to Vienna in 1532, or ban Nikola Šubić Zrinski who helped save Pest from occupation in 1542 and fought in the Battle of Szigetvar in 1566.

The 1526 Battle of Mohács was a crucial event in which the rule of the Jagiellon dynasty was shattered by the death of King Louis II. The defeat emphasized the overall inability of the Christian feudal military to halt the Ottomans, who would remain a major threat for centuries.

See also

• Bans of Croatia