The Diocletian Palace is one of the best preserved monuments of Roman architecture in the world. The emperor's palace was built as an adequate interpolation of various facilities of a luxurious villa – the summer residence created as a Roman military camp (castrum), and divided by two main streets into four parts. The southern part of the palace was in such a division as foreseen by the emperor, his apartments and appropriate governmental and religious ceremonial areas, whilst the northern part was foreseen for the emperor's guard – military, attendance, warehouses etc.
This palace is a rectangular building (about 215 x 180 m) with four large towers at the corners, there are four doors on each side and four smaller towers on the walls. The bottom part of the city walls has no openings whilst the upper floor is opened by a monumental cloister on the south side and corridors with huge arched windows on the other three parts. Over the centuries, the palace inhabitants as well as the Split inhabitants adapted these spaces, tailoring them to their needs, and so these buildings have notably changed their appearance, both on the inside and on the outer city walls with towers.