The Southern tower's walls, in particular, were changed into round shape in order to deflect cannonballs (circa 1370-1380s) and local captains at the time used Dubrovnik-made cannons, bombards, and balistas as the fortress' main defense weaponry.

The town population lived in houses along several main streets huddled around the central paved square built in Mediterranean fashion and the size of this old settlement has not grown significantly between early 13th to mid 19th century.

Here they set up camp and patiently waited since early June 1415 until most of the army finally gathered, pouring down from Hungary proper and Slavonia and as far away as Germany, Bohemia, Lithuania, and Poland.

Some of the units and weaponry were transported to the main Hungarian camp via boats, from river Sava down to river Bosna, which at that time flowed directly under the fortress (“...qualiter die XVI husus Johannes de Ghara cum multus gentibus scuritatis vestie appulerat in Uxora subtus castrum Dobuy qui ut fertur venit versus Bosnam”, Ragusan Council letter sent to Emperor Sigismund, dated June 28th 1415) .

To Hungarian dismay and against their expectations, most important Bosnian overlords - Hrvoje Vukčić, Sandalj Hranić, Pavao Radenović, and Vuk Zlatonosović from Usora Banate were present with their contingents.

In addition, there was a large contingent, of close to 15,000 Ottoman Turks under Isa-Beg that came to fight on the Bosnian side, arriving just in time from direction of Zenica and Lasva Valley.

However, as it was typical of the fickle politics in High Middle Ages in Europe, Bosnians gladly accepted Ottoman help this time in order to hit back at Hungarians which were incessantly waging wars and Crusades against them for the better part of last two centuries.

After careful positioning on the battlefield, the heavy cavalry charge opened the battle, with the smaller pockets of close quarter fighting subsequently developing on gentle slopes of the area set amidst rivers Bosna and Usora.

A-H army had losses of nearly 1,000 soldiers killed in the battle around Doboj in the late summer of 1878, on its way to Sarajevo, and as it tried to establish hold in Northern Bosnia.

While strategically obsolete, of note is that fortress remained in use by A-H forces in WWI and it stationed a strong Croatian Ustasha and German Wehrmacht unit in WWII.

Members of German forces built additional impromptu bunkers surrounded by concertina wire in the early summer of 1941, and due to its location and firepower, Serbian villagers were unable to take this object during their uprising on August 23, 1941 while they successfully captured all other objects and installations throughout the city and completely destroyed remaining barricaded German/Ustasha units in Doboj and surrounding area.

Several thousands Serb rebels, already under heavy Croatian Ustasha oppression since April 10 and establishment of Independent State of Croatia, managed to hold onto the city for 48 hours before being forced back across river Bosna as German armored units entered Doboj from Derventa/Brod and Tuzla area.

The lower layers of three flanking towers, in particular, remain inadequately researched with much more potential for future digs and detailed and long lasting conversation of this historical structure.