After two failed attempts in 1513 and 1514, Ottoman forces led by Ghazi Husrev Bey, sanjak-bey (governor) of the Sanjak of Bosnia, launched a major offensive on southern Croatia in the spring of 1522.

Croatian Ban Ivan Karlović, who was preparing a relief effort to help the besieged fortress, had Vojković imprisoned for surrendering the city.

Along with Skradin and Klis, the fortified city of Knin in northern Dalmatia, positioned on the upper Krka River, kept watch on the neighboring Sanjak of Bosnia.

[2] Following the death of King Matthias in 1490, the frontier zone came under increased Ottoman pressure,[3] and frequent raids left the forts isolated.

Knin, the capital city of Croatia and the seat of the ban, was slowly losing its status as the political and administrative center of the kingdom.

Its supreme court ceased to function, ban's deputy no longer had civil duties, and all efforts were focused on the buildup of Knin's fortifications.

[8] In 1501, Croatian Ban John Corvinus, with Venetian help, planned a larger offensive on the Sanjak of Bosnia from the direction of Knin.

[10] In a report on 5 May 1511 to the parliament in Buda, the master of the treasury, Blaž Raškaj (Hungarian: Balázs Ráskai), stated that Knin was continuously targeted by Ottoman assaults and that the entire Kingdom of Croatia would be lost if the city fell.

[13] Some local Croatian nobles made accommodations with the Ottomans to protect their possessions from raids, in the form of annual tributes to the sanjak-bey of Bosnia.

Venice reported that their coastal cities in the eastern Adriatic were no longer secure due to local agreements of Croatian forts in the hinterland with the Ottomans.

[10] Berislavić, whose tenure was marked with continuous battles with the Ottoman Empire, focused on defending the area around the Una River.

[13] The local population was decimated by war, hunger, plague, and migration to safer places, and the city's economy was hindered by the seizure of crops and livestock.

[21] The captains of Knin and Skradin traveled to Buda and offered their resignations in October 1521, explaining that they did not have enough resources to withstand Ottoman assaults.

King Louis II and his council persuaded them to remain in their positions,[22] and promised reinforcements of 1,000 infantry and 1,000 cavalrymen, though it is not known how many of these forces arrived to the two captains.

Karlović led an army to recapture it, and negotiated the surrender of the town in exchange for a free departure of mutineers to Ottoman-held territory.

The decision to let the Ottomans leave freely caused a quarrel with Keglević, who opposed such a move and complained about Karlović to King Louis.

Karlović's forces, numbering 2,000 cavalrymen and reinforced with troops from Austria, intercepted and defeated one Ottoman group returning to Bosnia in mid April.

Other Ottoman units made probing attacks on Knin and Skradin,[28] which were marked as the main targets in the first phase of the offensive.

[30] On their return from Carniola, Husrev Bey's forces raided the area around the towns of Grobnik, Ledenik, Brinje, and Modruš, in central Croatia.

[35] The Ottomans allowed civilians to remain in their conquered territories if they paid land tax (haraç), which was levied on non-Muslims in the empire.

[36] After hearing about the fall of Knin, the citizens of nearby Skradin fled and left the town undefended, which was then taken by the Ottomans without a fight.

[39] The fall of Knin was a huge shock in Croatia, and its loss accelerated the Ottoman advance in the southern part of the kingdom.

[41] Islamization in the western Dalmatian hinterland had less effect than in other regions, due to its distance, the activities of the Franciscans, and the special status of Vlachs in the Ottoman Empire.

Aid was expected from Austrian Archduke Ferdinand, who pledged to help regain the lost forts and strengthen the ones still under Croatian control.

The first ended with the capture of 24 Ottoman soldiers, while in the second one in July 1530, around 100 cavalrymen from Bihać reached the area of Knin and the Cetina River, where local Christian troops had been gathered by harambaša Nikola Bidojević.