Kastel is the oldest historical complex in Banja Luka and it represents the historical core, it is a witness of the past, the skeleton of the present and the guard of the future. Located in the very center of Banja Luka, the fortress has a rich history.
The surface of the Kastel complex is 48,000 square meters. The fortress walls consist of nine bastions and two towers. There are several facilities in the fortress, including a central camp with two towers. The early beginnings of the development of settlement on the site of Kastel originate from the Paleolithic era as indicated by findings of stone tools and weapons. The location of this settlement, which was still developing through the Neolithic and Bronze Age, is characteristic of the Baden culture as it is situated on the raised parts of the Vrbas river terrace.
Several examples of late antique bronzes, ceramics, and a late antique bronze fibula were found inside the fort. In addition, in the central part of the fortress are remains of the ancient fortified buildings of larger dimension, with a semicircular apse projection on the south side. Systematic research will determine whether it was an ancient Roman sanctuary, an administrative building or complex of different content.
There is an altar of the god Jupiter that was found in 1895. It is written on it: “To Jupiter, the greatest genius of this place Sicinius, from Makrin, consularbeneficiary of Upper Pannonia Province, he fulfilled his vow with gratitude”
In a charter from 1525 it is precisely stated that Banja Luka is actually a name of a fort named ‘Castell Nostro Bagna Luca’. From the content of the charter, one might even conclude that the Banja Luka fortress was built on the site of an older and smaller fortification after 1463, as part of the border on Vrbas in the defense system of the Kingdom of Hungary against Turkey (Jajce was the southernmost point).
Kastel continues to play a very important role in Banja Luka. Not only it is a symbol of tradition, it is also the location for numerous cultural events.