he ancient fortress is situated on the hill “Kaleto” or “Gradishteto” in the southwest from Montana, at about 40 m. elevation above city level. As a result of archeological excavations, a city gate and a big tower have been uncovered – a brilliant example of III – IV century fortress construction. Few more military and civil buildings have been uncovered too, basilica and masonry from the Roman empire, buildings from the stone – copper age in the lowest cultural layers, as well as Slavic dwellings and a sanctuary.
     The first settlement at this strategic and easy to protect elevation, with its rich water spring, is from the stone – copper age (IV millenium B.C.). A Thracian village, which has been fortificated with a massive wall (with preserved thickness of more than 1 meter), following the outline of the area and dating back to the end of the early iron age.
     The significance of the hill has been appreciated by the Roman authority. The fortifications have probably been built with the very beginning of the Roman occupation (The First Sugambrian cohort, which took part in the Thracian uprising suppress from 26 A.D.). A village starts growing around the military camp (first mentioned in an epigraphic document from 134 A.D.), and the ancient sanctuary near the water spring. In 160 – 161 the village is given municipal right – i.e. a statute of a town with surrounding territory. The name of the town – Montana has been saved in a manuscript from the II century.
     The economic and cultural advance of Montana from the II – IV century is interrupted in the middle of the III century by the Gothic invasions. At the threat of new barbarian invasions, building of a fortress has been started. When this invasions become more frequent in the IV or V century, a second fortress wall has been built to the south and east.
     The fortress is destroyed in VI – VII century in one of the Avarian or Slavic raids. A Slavic village has been built lately over the ruins.