Following the fall of Počitelj on the Neretva River in 1471, the whole land between Cetina and Neretva rivers except the coastline fell into Ottoman hands. To prevent further Ottoman expansion, King Matthias Corvinus named Nicholas of Ilok titular King of Bosnia. The Kingdom of Bosnia was conquered by the Ottomans in 1463 and their last king Stephen Tomašević was beheaded by Mehmed II. Soon Nicholas of Ilok was named Ban of Croatia and Slavonia, making them a single administrative unit. His task was to take the parts of Bosnia that were still held by the Ottomans, but he failed to do so. Following his death, King Matthias broke into Bosnia and reached Sarajevo, however, his success was temporary. In 1482 the Ottomans conquered all the remaining strongholds in Herzegovina. That same year Ottoman forces from the Sanjak of Bosnia plundered Carniola, while in 1483 they ravaged the surroundings of Ptuj in Lower Styria.
Battle
In early October 1483 Sultan Bayezid II sent a large Ottoman force of around 7,000 Akıncı, led by Harsi Pasha and Serli Hasan, that crossed the Una and Sava rivers and broke into Croatia. The most affected areas were the countrysides of Jastrebarsko and Petrovina. Their army was split into 3 parts, each going its own course, with one continuing towards Carniola and Carinthia on 16 October. Matthias Gereb, who became the Ban of Croatia that year, was informed about the raid, but he lacked the forces to confront the Ottomans. Therefore, he started assembling an army with the Croatian nobles; Count Bernardin Frankopan, Ivan Frankopan Cetinski, Mihovil Frankopan Slunjski, Petar Zrinski, and ban deputy Gašpar Perušić, who were later joined by Despot of Serbia Vuk Grgurević and Blaise Magyar. A part of the Croatian cavalry was sent to track the Ottomans on distance and if an opportunity comes up to intercept them. On their way back the Ottoman armies merged into one, leading many captives that were slowing them down. Upon hearing of a large army trailing them, the Ottomans tried to evade a fight and reach the Bosnian Sanjakwithout a trace. The Croatian army waited for them at the Una River crossing near Brod Zrinski. Since there was no other crossing nearby, fighting started on 29 October. The battle was halted by nightfall, during which the Ottomans took position at the foot of a nearby hill. Fighting continued the next day at dawn and resulted in a total defeat of the Ottoman army. Around 2,000 Ottomans were imprisoned, while more than 1,000 fell on the battlefield. According to a report from King Matthias Corvinus, 10,000 Christian prisoners were liberated. The King sent a special letter of gratitude to Ban Matthias Geréb and the Croatian nobles and informed Pope Sixtus IV about the victory on 6 November.
Aftermath
Shortly after the battle a 7-year truce was signed with Sultan Bayezid II that lasted until the death of King Matthias Corvinus in 1490. Although during that time no major battles were fought, local border clashes continued. The Sultan used this truce to strengthen his rule and prepare fresh forces for new conquests and the expansion of his Empire westward, that continued in 1490. Croatia had another victory against the Ottomans in the Battle of Vrpile in 1491, but also a huge defeat in the Battle of Krbava Field in 1493.
