AQUAE CALIDAE (Milen Nikolov – m_kotlenski@abv.bg) During sondage explorations, Late Antique and Mediaeval material was found. The southwestern corner of a building belonging to the thermae was discovered. It was built of ashlars up to 2.40 m by 0.60 m by 0.50 m in size bonded with mortar that were reused from an earlier building. The walls were 1.10 m wide, built of two rows of ashlars. The floor was paved with bricks 32 cm by 32 cm by 5 cm in size, arranged over a mortar plaster. A layer up to 45 cm thick was discovered under the building platform, containing a few sherds of the 6th century AD and a follis of Justin II minted in AD 574 in Nicomedia which was terminus post quem for the construction of the building. A stratum 1.20 m thick was discovered, containing material of the 6th century AD, including two coins of Justin II. A layer with traces from fire was documented on top of it and a stratum 20 – 25 cm thick with sherds of the end of the 11th – 13th centuries was situated above. Another layer with traces from fire was documented over it. The Roman and Early Byzantine baths measured 71 m by 56.50 m and the mineral spring was situated in their center. A corner of a building of the 6th century AD constructed of rubble masonry was discovered and several Christian graves of the 11th – 13th centuries were explored.