[2] Archeological research on the substructures over the past 70 years has revealed evidence of new structures, predating the palace by two centuries.

[3] During the later Roman empire, the function of the cellars was partly to elevate the Emperor's chambers on the floor above, but they were also the storage area for foodstuffs and wine for the Palace.

[3] In the Early Middle Ages, as refugees made their homes behind the safety of the palace walls, a part of the underground complex was used as a residential area.

It is suggested that the eastern section of the cellars partially collapsed during this time, and resulting in the destruction of the monastery.

The Western part of the basement has been preserved in its entirety and is almost completely accessible for sightseeing, used as an attractive fair[6] and exhibition space.