An aerial view of the newly excavated ruins of the water cistern of the medieval Byzantine and Bulgarian fortress Rusocastro in Southeast Bulgaria. Photo: Burgas Regional Museum of History
Archaeologists have discovered a huge water cistern plastered on the inside with pink waterproof mortar in the fortress of Rusocastro, a major stronghold which changed hands many times between the Byzantine and Bulgarian Empires in the Middle Ages, and whose ruins are stiuated in today’s Burgas District in Southeast Bulgaria.
The water cistern of the Rusocastro Fortress is estimated to have the capacity to store at least 300 cubic meters of water (app. 10,600 cubic feet), the Burgas Regional Museum of History has announced.
It has been discovered at the very end of the 2017 archaeological excavation of the fortress, which is the largest medieval fortress in today’s Southeast Bulgaria, and is said to have had the largest castle in the region.
In September 2017, the Burgas Museum announced the discovery of the “monumental" staircase leading up to the castle of the Rusocastro Fortress.
In July 2017, the archaeological team excavating the major fortress discovered a rare 10th century ivory icon believed to have belonged to a Byzantine Emperor or a member of the Byzantine imperial family, and to have been made in Constantinople.
Before that, the Burgas Museum had just announced the discovery of a 7th century gold coin of Early Byzantine Emperor Phocas (r. 602-610 AD).
The Rusocastro Fortress is best known for the Battle of Rusocastro in 1332 AD. It was the last big military victory of the medieval Bulgarian Empire before it was conquered by the invading Ottoman Turks at the end of the 14th century.
In it, Tsar Ivan Alexander (r. 1331-1371) of the Second Bulgarian Empire defeated Byzantine Emperor Andronicus III Palaeologus (Andronikos III Palaiologos) (r. 1328-1341 AD).
The newly discovered water cistern in Bulgaria’s Rusocastro Fortress has been found in the southeast corner of the fortress citadel.
Its western wall is 15 meters long, its eastern wall is 12 meters long, and it is 8 meters wide. Its northwest corner is shaped as an arc.
Two massive stone pillars were erected inside the water cistern, which had an arched roof. As the roof collapsed, huge chunks of it have fallen inside the tank, and have been preserved in there, the Burgas Museum explains, adding that they are to be extracted in 2018.
The water cistern of the Rusocastro Fortress was protected by the southern and eastern fortress wall of the fortress castle which were 2.5 meters wide, and by a large fortress tower which was 7 meters in diameter.
The water cistern has also been found to have had a “second floor", which a staircase leading up to it.
The newly excavated ruins of the water cistern of the medieval Byzantine and Bulgarian fortress Rusocastro in Southeast Bulgaria. Photo: Burgas Regional Museum of History
“The inside walls of this monumental facility were carefully covered with a thick, hydrophobic (waterproof) mortar plaster," the Burgas Museum of History says.
“The plaster has a deep pink color because a large amount of crushed baked ceramics, which actually give it the waterproof qualities, was added to it," it explains.
The archaeologists are yet to process the discovery pottery, study the newly discovered coins, and analyze the animal bones discovered in the latest digs in order to learn more about the food of the medieval Bulgarians and Byzantines in the 13th-14th century.
The Rusocastro Fortress had a territory of 52 decares (app. 13 acres), making it the largest medieval fortress in today’s Southern Bulgaria, and comparable in size to the key medieval fortress in today’s Northern Bulgaria such as the citadels of Tarnovgrad (today’s Veliko Tarnovo), Tsarevets and Trapesitsa, and the cities of Cherven and Kaliakra.
The walls of the Rusocastro Fortress have been preserved up to a height of 5 meters.
The Late Antiquity (Early Byzantine) and medieval Bulgarian and Byzantine fortress of Rusocastro(Rusocastron) is located in today’s Southeast Bulgaria, close to the Black Sea city of Burgas. Rusocastro was also known as “The Red Fortress" because of the red stones it was built of.
In the 2nd millennium BC, the Ancient Thracians set up a shrine of the Sun God, the Mother Goddess, and the Thracian Horseman, also known as god Heros, near the legendary cave known today as Rusina Cave or Rusa’s Hole. Its site was settled in the period of Ancient Thrace, and was an important center in the Thracians’ Odrysian Kingdom.
The fortress itself was built in the 5th century AD on a strategically located hill. The Early Byzantine fortress was most probably destroyed in the Slavic and Avar invasions in the 7th century. The Rusocastro Fortress was rebuilt by the Bulgars in the 9th century, during the First Bulgarian Empire (632/680 – 1018 AD), at the time of the construction of the Bulgarian border rampart known as Erkesiya (in use in the 9th-11th century), and was a major stronghold in the geographic region of Thrace during the High Middle Ages.
The earliest written information about the Rusocastro Fortress comes from a 6th century epigraphic monument dedicated to Byzantine military commander Justin, who, according to some Bulgarian scholars, was the great-grandson of Byzantine Emperor Justin I (r. 518-527 AD), the uncle of Emperor Justinian I (r. 527-565 AD). The name Rusocastro was first used in the 12th century by Arab geographer El Idrisi in his work “Geography of the World", where Rusocastro is described as a large and crowded city. The fortress was also mentioned in a number of Byzantine sources from the 14th century relevant to current events.
The Rusocastro Fortress is famous in Bulgarian history for the Rusocastro Battle in which the army of Bulgarian Tsar Ivan Alexander (r. 1331-1371 AD), ruler of the Second Bulgarian Empire (1185-1396 AD), defeated the forces of Byzantine Emperor Andronicus III Palaeologus (Andronikos III Palaiologos) (r. 1328-1341 AD) in 1332 AD.
The Battle of Rusocastro is often referred to as the last big military victory of the medievalBulgarianEmpire before its conquest by the invading Ottoman Turks at the end of the 14th century.
Tsar Ivan Alexander’s victory at Rusocastro is considered the last major military victory of the Bulgarian Empire before its decline in the second half of the 14th century, and its conquest by the Ottoman Turks that ushered in the darkest page in Bulgaria’s history, a period known as the Ottoman Yoke (1396-1878/1912). The Rusocastro Fortress was ultimately destroyed in Ottoman campaigns in 1443.
Rusocastro has been excavated by archaeologists Milen Nikolov and Tsanya Drazheva from the Burgas Regional Museum of History. The Bulgarian archaeologists have excavated several churches there including a monastery named after St. George, which existed in the 11th-14th century. Unfortunately, a Christian necropolis in the Rusocastro Fortress was partly destroyed in the largest military drills dubbed “Shield" of the countries from the former Soviet-dominated Warsaw Pact that took place in Eastern Bulgaria in 1982.