Two years after the completion of the Roman baths, Carnuntum’s Roman city quarter was expanded by another attraction. Built around the only surviving Roman floor mosaic in its original location, the semi-reconstructed domus quarta depicts the lavish lifestyle of upper middle class Carnuntum. It was when the entire area of this spacious dwelling was first exposed in the early 1950s that the archaeologists came across this floor mosaic. For reasons of protection, the mosaic was covered up again after the excavations remaining hidden for decades. In-depth excavations between 2008 and 2011 revealed fascinating new information about the social status of the former owner. Apart from the floor mosaic, researchers found a small, private bathroom as well as an own water supply. These facts confirm the high social status of the proprietor, who is likely to have belonged to the upper middle class of Carnuntum.

In order to present the mosaic floor to the visitors, it was carefully removed, meticulously restored and finally re-embedded in its original place. The reconstructed room may have served as a representative dining room in ancient times during the warm summer months.