The battlefields were concentrated in the central-eastern areas of the Kingdom of Croatia, stretching from the eastern border of the pre-Ottoman times to the eastern border of the "reliquiae reliquiarum olim inclyti regni Croatiae" ("remnants of the remnants of the once great kingdom of Croatia").

After the 1493 Croatian defeat at Krbava, the Ottomans started the occupation of significant forts: Knin and Skradin fell in 1522.
The Battle of Mohács happened in 1526.
Jajce fell in 1528, Požega in 1536, Klis fell in 1537, Nadin and Vrana in 1538, moving the Croatian-Ottoman border to the line, roughly, Požega-Bihać-Velebit-Zrmanja-Cetina.

By the end of 1540, the Ottoman Empire occupied the Croatian possessions between Skradin and Karin, eliminating them as a buffer zone between the Ottoman and Venetian territory in Dalmatia.
By 1573, the remainder of the Dalmatian hinterland, now largely controlled by the Venetian cities, was even further reduced by Ottoman advances.
The battlefields were concentrated in the central-eastern areas of the Kingdom of Croatia, stretching from the eastern border of the pre-Ottoman times to the eastern border of the "reliquiae reliquiarum olim inclyti regni Croatiae" ("remnants of the remnants of the once great kingdom of Croatia").
After the 1493 Croatian defeat at Krbava, the Ottomans started the occupation of significant forts: Knin and Skradin fell in 1522. The Battle of Mohács happened in 1526. Jajce fell in 1528, Požega in 1536, Klis fell in 1537, Nadin and Vrana in 1538, moving the Croatian-Ottoman border to the line, roughly, Požega-Bihać-Velebit-Zrmanja-Cetina.
By the end of 1540, the Ottoman Empire occupied the Croatian possessions between Skradin and Karin, eliminating them as a buffer zone between the Ottoman and Venetian territory in Dalmatia. By 1573, the remainder of the Dalmatian hinterland, now largely controlled by the Venetian cities, was even further reduced by Ottoman advances.
Hundred Years' Croatian–Ottoman War