ARCHAEOLOGICAL EXPLORATIONS IN SEXAGINTA PRISTA (Varbin Varbanov – ramonearhaeology@abv.bg, Deyan Dragoev) Ten Thracian pits, 1.30 – 3.28 m in depth and 0.90 – 1.70 m in diameter, were explored. The pits contained fragmentary wattle-and-daub, Thracian sherds, sherds from local imitations of Megarian bowls, Celtic sherds with graphite decoration and a fibula of the Aucissa Type dated to AD 20 – 80. The pits dated to the 2nd century BC – 1st century AD. The floor of bricks in the Principia of Castellum Sexaginta Prista was explored. The floor was cut by pit No. 1, dug out after the beginning of the 5th century AD when the Principia already did not function. Three coins of the first half of the 4 century AD discovered between the bricks of the floor and the mortar layer and another one found inside the mortar layer were indicative of the chronology. They show that the Principia and the Castellum were built during the reign of Constantine the Great. Two pits were discovered under the floor of the Principia. Pit No. 2 contained eight coins, the latest one minted by Diocletian in AD 292. Pit No. 3 contained three coins, the latest one minted by Maximian in AD 293. Pit No. 3partly destroyed pit No. 4, which contained pottery of the 3rd century AD. A fragment of marble votive relief and nine coins, the latest one minted by Maximian in AD 285 – 286, were found in the area that was explored. A quadrilateral base of a column belonging to the temple of Apollo was discovered. During the archaeological excavations, 25 Roman coins were found: an as of the 1st century AD, six coins from the first half of the 3rd century AD, 13 coins from the last quarter of the 3rd century AD, four coins from the first half of the 4th century AD and one unidentified.