In the western part of the archaeological area is located an articulated monumental complex called “Domus of marine mosaics.” The known building is on two levels and rests on the rock walls of the hill. It is particular for the distribution of rooms, the presence of numerous mosaic coverings depicting different species of fish, and the rich decorative apparatus with colored marbles. Recent archaeological investigations have uncovered part of an inscription in the frame of a mosaic floor, reading “Deo gratias qui praestitit“, which can be translated as “thanks to God who provided.” This is evidence of the environment’s use as a place of Christian worship in the 4th century AD, and is the first time it has been found within the urban perimeter of Turris Libisonis. The original use of this space, characterized by a series of seats on all sides, appears to correspond to a locker room (apodyterium) functional to the spa facility. The features support the hypothesis that the building experienced at least two periods of use, one ascribable to the 3rd century AD and a final one from the 4th-5th centuries AD. The pottery and coins found are also almost all pertinent to a period between the second half of the 4th and early 5th centuries AD.