In the course of archaeological excavations in the imperial palace over 350 m² of mosaic pavements have been uncovered. The pavements belong to different building phases in the palace; the earliest is dated to the end of the third century, and the most recent phase to the middle of the fourth century. The majority of the pavements are geometric polychrome mosaics (known as “geometric carpets”) which are typical of the late Roman Empire. The mosaics are executed in the western style and have analogies with the mosaics in Diocletian’s Palace in Split.
The mosaics are worked in the technique known as opus tessellatum (consisting of small square pieces of stone - tesserae); the decorative motifs employed are geometric, floral or various guilloche and cable patterns. Only one mosaic with a figural representation is preserved, of the god Mercury.
The mosaics from the palace complex are the best examples of this type of pavement found in Sirmium to date. Their high quality attests the superior standards of workmanship which are typical of tetrarchic architecture in the Balkans.