Various written sources, archeological findings as well as the remains of tools attest to the Turkish Osijek during the 16th, 17th and 18th century, as well as to sites that were built during the Ottoman rule. All the evidences that have been collected indicate that Osijek was historically significant town that suffered major transformations over the course of its history. Today the relic enshrined into the urban fabric and structure is the town's oldest, baroque monument. Tvrđa was much more than a military fortress and complex fortification, military object and army. As a town- fortress with the Inner Town, Tvrđa had a crucial impact on the development, structure and appearance of the town as we know it today. The first chronicles written during the Ottoman period give an insight into the everyday life of the population. Moreover, the first plan of Tvrđa shows its form with 4 gates and a hornwerk, while the second plan shows the fortifications as well as the Crown fortress on the left bank of Drava river. The third and the fourth plan significantly differ from the first two since they were based on the construction of the completely new fortress. The fourth plan shows the fortress built in accordance with the most advanced construction achievements of the period. This paper follows the changes and construction of the new objects, as well as the cultural achievements and famous people that Osijek is proud of today.