Colonia Ulpia Traiana Augusta Dacica Sarmizegetusa, founded by emperor Trajan, was the first Roman city in the newly conquered province of Dacia. This paper focuses on the area located in the very heart of the city, occupied during the Severan period by the temple dedicated to the Palmyrene gods. The temple overlapped a domus with two different construction phases. During the archaeological excavations, fragments of painted walls belonging to the first phase of this domus were discovered. This paper aims to show how the decoration of the building evolved, particularly when we are dealing initially with a domestic use of the area, along with a religious and sacred one later. How a place is decorated gives us insights into the Roman way of life in the province of Dacia. Taking into consideration the multitude of meanings one could apply to the concepts of place and space, it is important to see how the perception of a monument has changed over time.