SOSTRA (Ivan Hristov – ivchristov70@abv.bg) The explorations continued in the eastern part of the castellum, in Sectors II – III. There were no houses built to the west of the fortification wall constructed of uneven stones bonded with mud. Probably the early fortification wall, situated in front of the eastern fortification wall of the second half of the 2nd century AD, was temporary. The fact that the construction of the early fortification wall was abandoned could be explained with changing the plans for dislocation of the cohors milliaria with cohors quingenaria instead. The explorations to the west of the fortification wall of the end of the 3rd century AD show the existence of fortification structures and houses. The interior rectangular fortification tower, the second one to the south of Porta Praetoria, dated to the second half of the 2nd century AD. During the second half of the 3rd century AD, the tower was cut by the construction of the late fortification wall and in the 4th century AD it was cut by rooms adjoining the inner side of the eastern late fortification wall. Two streets were documented to the west of the tower. The first one was via sagularis, synchronous to the construction of the earliest military camp by Сohors II Mattiacorum. A barracks was documented close to the street, dated by sherds of the 2nd century AD, a bronze fibula, two denarii of Trajan and Hadrian, a bronze coin minted by a later member of the Antonine Dynasty discovered in a layer with traces from fire. A street of the end of the 4th century AD was documented at 70 cm above the earlier street. Finds from the excavations included bones from domestic and wild mammals, river shells, Roman provincial bronze coins minted by Marcianopolis and Nicopolis ad Istrum, bronze plates from plated mails, a fragment from small votive relief, a gold finger-ring and pottery of AD 150 – 250.