v. Lomets. Municipality Troyan. State Lovech.
The Roman military encampment Sostra is situated 12 km north of Troyan and 28 km south of Lovech. At the place are found a lot of coins, utensils, memorial stones. The most intriguing find is an ancient Trakian mask dated about V-IV century before Christ. It is found on pieces and is restored. The mask is now kept in the National Historical Museum in Sofia.The castle is built on a comparatively flat terrain, in the valley of river Osam, and surrounded by low hills, with height of no more than 500 m above the sea level. The castle is build near the junction of rivers Ladana and Osam. The above sea level of the castle is 300 m. Its location is exceptionally strategic, for it controls the approaches to Troyan, to the south, and the road goes right next to it. The eastern (main) gate of the castle points towards the area `Kalugerskoto` - the only known approach to the upper course of river Osam. The whole valley, in which the castle is situated, covers an area of about 4 sq. km. In the valley are localised and partially explored many objects, described in the volume I of the series `Sostra`.
The name of the Roman roadside station Sostra is earliest marked on the so-called `Peutingerian map` (Tabula Peutingeriana) at the end of the IV century. The station, along with all the surrounding constructions, is situated on the road Escus - Philipopolis, outlying 13 Roman miles south of Melta (probably north of Lovech) and 10 miles north of Ad Radices (the area `Popina laka` - east of B. Osam village, Troyan municipality). Sostra, as a name, is also found in some west European maps from the XVII - XVIII century, mostly based on the Peutingerian map. The name of the station probably comes from the ancient Greek words Sworpa, Sworpov (bandage, belt), which corresponds to the strategic location of the antique compound of roadside station, castle and constructions surrounding them in the valley of river Azamus (Osam). The Hungarian historian Felix Kannitz is the first who said that Sostra had been found in the surrounding area of Lomets village. K. Irechek, V. Avramov, V. Dobruski, M. Madzharov, G. Kitov, T. Totevski are among the first explorers of the Roman remains. The first complete research of the fortified military camp (castle) and roadside constructions is made by an expedition from the National History Museum in the summer of 2002. The expedition is part of a three-year scientific program. Engaged in the realisation of this program are Prof. Dr. Rumen Ivanov (Archaeology Institute and Museum /AIM/ - Bulgarian Science Academy /BSA/), Dr. Sergey Torbatov (AIM - BSA), Dr. Ivan Hristov (National History Museum /NHM/) and Maria Ivanova (Archaeology Museum `Maritza-Iztok` - Radnevo).
The most valuable and intriguing find is an ancient Trakian mask dated about V-IV century beofre Christ. It is resotered and is being kept in the National Historical Museum in Sofia.
From 1900 to 2003, on the territory of the Roman castle and roadside station Sostra were found 12 full or fragmented epigraphical monuments, most of them from the II and III century. In chapter III of the volume, are classified and described all of the known epigraphical monuments till 2003. The presented monuments can be divided in three relative groups: I. Official inscriptions, raised by the commanding officers of the cohorts stationed in Sostra.
III. Votive offering inscriptions, devoted to different gods from the Greek - Roman and Thracian pantheon. The earliest and most valuable epigraphical monument is found in the year 2001 in the principia of the castle. It is a base of an emperor\\\'s statue, with 9 rows Latin inscription on it. From this inscription we learn, that about the year 14-15 AD, during the rule of emperor Antonin Pee, at Sostra has been billeted the first impressive, for these times, militari unit - II Matiacian cohort, consiting of 1000 infantryman. This subdivision is also connected with the building of the castle in the beginning of the III century.