Development of the military settlement at Tvrđa started in 1687 when the Habsburg armies drove the Ottomans out of the city during the Great Turkish War. The chief commander of the Imperial army, Louis William, Margrave of Baden-Baden, saw Osijek as a location of exceptional strategic importance in the war against the Ottomans. He urged the repair of the city walls, and proposed construction of a new fort according to Vauban's principles of military engineering.
The town magistrate was established in 1690, while the plans for the new fort were still being drawn up, and one of its documents from August of the same year described the condition of the settlement as "ruinous". Two months later, on 29 October, the Ottoman army suddenly attacked. The attack was repulsed only thanks to a well-organised defense, and the Turks withdrew on 6 November, after a brief siege. The event was a clear lesson that the construction of the fort must not be delayed any further. The first phase of Tvrđa's conversion into a Baroque fortress was based on the plan devised by the engineer Mathias von Kaiserfeld from 1691
Uploaded: Oct 29, 2015