A sophisticated architectural complex was developing in the south- eastern part of the Inner town whose construction began in the end of the 9th- 10th century. Including several buildings with different purposes it is a proof for the high level of architectural concept and town planning of medieval Preslav.

The small bathroom. Found in 1971 as an isolated building today the small bathroom is a part of this palace group. In plan it is of suite type with three rooms separated by brick partition walls i.e. there was a  passage from one room to another. The ground floor which is dug into the surrounding terrain includes a fireplace in the eastern section and hypocaust of clay pipes which pass into the other two rooms. Hot air circulates through these pipes coming out of prefurnium with vaulted holes. The floor level of the real bathroom is erected on 0,60 m. higher and is on the hypocaust pipes. There are hot water boilers in the eastern room, the second (middle) one is designated for a changing room and the western one is the real bath (bathroom) with a bathtub in it. Hot water reached this room through inner installation of lead pipes and the building’s entire supply was organized by a water pipe consisting of clay tubes, passing in parallel to the outer northern wall.

The small bathroom in the Palace center of medieval Preslav is a classically planned scheme adopted in the proto- Bulgarian bath construction in the end of the 9th and 10th century. It proves that high level of development of the Preslav civilization and culture.