The original plan for Tvrđa was drafted because of the need to reinforce the town walls, but did not include provisions to redesign the interior and envisaged largely uncontrolled development. New plans for a fort on the right bank of the River Drava were drawn up by Maximilian Gosseau de Henef. Gosseau took over planning of the fort when construction was already under way. Starting in August 1712, Austrian engineers, supervised by the fort's commander, General Johann Stephan von Beckers, built barracks, staff headquarters, churches and monasteries, surrounded by system of moats, bastions and gun positions, respecting Gosseau's design. The design followed the model of lowland Dutch military fortifications of the period.