The Diocletian's Palace is an ancient architectural complex build in 305 AD and planned to be the retirement home for the Roman Emperor Diocletian. After Roman times, the palace was converted into an inhabited fortress, which over time adapted to different cultural influences. Numerous buildings as well as structural changes from different epochs testify to the lively history of the Croatian port city of Split, whose core today is the palace. The palace was declared a World Heritage Site by UNESCO in 1979. In order to get to know the palace, to understand it better and its inseparable historical developments, I spent a while researching and analysing the historical changes through available literature from the 4th century to the present time. During my stay in Split, the south-eastern part of Diocletian's Palace caught my interest because it was created differently than the rest of the palace. While the western part was built in the antique times and preserved since, the eastern part was often neglected and forgotten in the past. Until the beginning of the 16th century the complex was in archiepiscopal possession. After the archbishop's palace was destroyed, a free space was created over the cellar rooms. This part was rebuilt from the second half of the 16th century. These new constructions are not related to the antique grid of the cellar. Some basement rooms have not yet been excavated and are therefore inaccessible to the public, which was very exciting and extremely interesting to me. Thanks to the head of the Institute for the Protection and Restoration of Architectural Heritage, Prof. Katja Marasović, as well as institutes friendly staff, I received the required documents and was able to examine them, but above all I received recommendations on what are reasonable and acceptable possibilities to intervene without disturbing already existing parts of the palace. The present work is divided into three sections: the first part is devoted to the develop-ment in general, as well as the geographical and historical development of Croatia, Dalmatia, Split, Diocletian's Palace, South eastern Palace and its previous territorial development, revitalization of cellars, research and reconstruction to the present time. Based on this, the second part will be used to carry out the extensive construction site analysis. In the third part I am going to present the concept, the design and the detailed planning and visualization.