Systematical archaeological excavations at the site Gamzigrad - Felix Romuliana continued in 2007-2008 in the south-eastern part of the fortified imperial palace, in the section of the thermae according to the plan of archaeological research for this site (2005-2009). In 2007, squares L'XXIV, M'XXIV, M'XXIH and M'XXII, which were investigated in 2005 to the horizon c, dated to the end of the 5th and the beginning of the 6th centuries, were completely excavated to the level of the porch of the earlier fortification of Romuliana (Plan 1). The stratigraphy of the cultural layers in these squares is as follows (Fig. 1): Below horizon c there is a layer of construction rubble mixed with brownish-yellow, clay like, sandy soil, 50-75 cm thick, comprising the finds dated in the last quarter of the 4th-5th centuries, layer D; The level of layer D is horizon d, where a structure destroyed in a conflagration, house 1/07, was discovered in squares M'XXII and M'XXIII. It could be dated, on the basis of the preserved household (pottery, metal and antler items, coins, etc.), from the last quarter of the 4th to the middle of the 5th century; Horizon d 1 is a mortar floor discovered beneath horizon d, which presents the earlier phase of house 1/07; Horizon d 2 is the earliest mortar floor inside the house 1/07, covered with a later mortar floor (horizon d 1) and a levelling layer of yellow sand and gravel, which comprises the finds dating also to the last quarter of the 4th to the middle of the 5th centuries; Layer E, 15-40 cm thick, is below horizon d, comprising dark brown soil with rubble and lenses of soot at the bottom, together with finds dated to the second half of the 4th century; Horizon e is covered with layer E, and spread across all the squares which were investigated to the south and to the east of Galerius' bath, where 8 large postholes, which outlined a space 7 x 3 m large and probably some kind of porch, were found along with two furnaces and two pits; Layer F, about 30 cm thick, is the substructure of horizon e and it comprises crushed stone and pebbles mixed with lime mortar, and in places has a levelling of reddish-brown sand. Finds here were dated to the end of the 3rd and the first half of the 4th centuries; Horizon f is a mortar floor of the later fortification of Felix Romuliana at a level of 184.75 m in the west and 184.55 m in the east (an average level of 184.64 m), which was interrupted by a trench running in an east-west direction along the southern section of squares L'-M'XXIV. The trench was filled with soot, small rubble and reddish-brown sand and comprised a large amount of artifacts, such as pottery and glass fragments, metal and bone items and coins dated to the second half of the 3rd century (Fig. 4). Layer G consists of dark brown and yellowish-brown clay with small rubble and soot. It was a levelling layer above the intense construction rubble from the previous horizon and a substructure of horizon f. This layer comprised archaeological finds dated to the end of the 3rd and the first half of the 4th centuries and to the prehistoric period (Early Iron Age); Horizon g is a mortar floor of the porch of the southern and eastern rampart of the earlier fortification of Romuliana. 4 pillars of the eastern porch (pillars 1-4, discovered in 2004-2005), a corner pillar in an L-shape (pillar 5) and one pillar of the southern porch (pillar 6) have been ascertained. From this level the water and sewage canals were dug (Fig. 5). In squares K'XXII-XXIII a trench, measuring 4 x 2 m, in an east-west direction, was opened which aimed to investigate the layers beneath the Roman horizon g. The stratigraphy in this trench is as follows: - Layer G at a level of about 184.53 m; - Layer H, about 35 cm thick, is greenish-yellow clay in which Roman canals were buried, comprising the fragments of the Early and Late Iron Age pottery and fragments of reddish rammed earth (Fig. 2); Layer I, about 20cm thick, is greenish-brown clay, comprising the scarce fragments of the Early and Late Iron Age pottery; Virgin soil consists of yellow clay starting from a level of 184.00 m in the west and of 183.60 m in the east. In 2008, the remains of an earlier building were discovered beneath the floor of the apodyterium of Galerius' bath found in 2002 and below the foundation of the sudatorium and the tepidarium of the same structure, which were found in 2005. Also, for the purposes of conservation and restoration of the thermae, an apsidal room next to the west wall of the apodyterium, so called 'Galerius' dressing room', was completely filled with construction rubble, among which was found a part of an abraded vault (Fig. 6). Excavations proved that the apsidal room had been a pool with cold water, a frigidarium, which was twice renovated and was decorated with mosaic made of black, white and grey stone cubes (Fig. 7). The phases of reconstruction of the frigidarium could also be noticed in its eastern wall (Fig. 8). Also in the rubble inside the pool, glass mosaic cubes of deep blue and golden colours were discovered, indicating the decoration of the vault. In the latest phase, two pillars were constructed to carry the stairs made of stone slabs (Fig. 8). The earliest phase of this room, which had a rectangular layout and a mortar floor, could be part of the building dating back to before Galerius' bath (Plan 2). During the cleaning of the eastern wall of the frigidarium, a semicircular niche with a fresco decoration of geometrical and figural motives, painted in black, dark red, orange and blue on an ochre surface, was discovered (Fig. 3). Under Galerius' bath, a large earlier building was investigated (trenches 1-5/08). Only its foundation zone is preserved. The walls of the Imperial bath were founded on the earlier walls, which were 0.65 m thick and had foundations which were 0.90 m thick (Plan 2). The pilaster of the west faeade of the thermae was also founded on the earlier wall, but it destroyed a water canal (canal A discovered inside the south room of Galerius' bath in 2004), which was constructed after the earlier structure and before the Imperial bath (Fig. 9). It is interesting that the part of the earlier building to the west of the thermae was not demolished during the construction of the Imperial residence. It was adapted and incorporated into the plan of the fortified palace. The original construction was a large public building, probably theprincipia, with a row of rooms around a large courtyard, the atrium. The entrance, which had a porch and a pylon with two square towers and thresholds made of stone slabs, was in the north. (Figs. 10-14) Previously, this building was mistakenly dated to the 4th-5th centuries, because it had been reused in Late Roman and Early Byzantine periods. (Figs. 15-18) However, based on the results of the new research, it could be dated to the 3rd century. .
