Second Bulgarian Empire Demolished 6th Century Byzantine Walls of Rusocastro to Build Far More Massive Fortress, Archaeologists Find

An aerial shot of the newly excavated 68-meter-long western fortress wall of the Rusocastro Fortress which lies on a volcanic hill. Photo: Burgas Regional Museum of History

The 6th century AD Early Byzantine fortress walls of the Rusocastro Fortress in today’s Southeast Bulgaria were almost completely demolished by the Second Bulgarian Empire in the 13th century so much more massive walls could be erected, the archaeologists excavating the site have concluded.

The archaeological team researching the Rusocastro Fortress has announced this discovery together with the completion of the excavations of the entire western fortress wall of the major medieval Bulgarian and Byzantine stronghold.

The researchers point out that the outer walls of Rusocastro, the largest medieval fortress in today’s Southeast Bulgaria, are so massive that they are comparable only with the fortress walls of Tsarevets and Trapesitsa, the two main citadels of Tarnovgrad, today’s Veliko Tarnovo in Central North Bulgaria, which was the capital of the Second Bulgarian Empire for 208 years (1185 – 1393).

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).

During the 2018 excavations, the archaeologists have exposed a section of 48 meters (appr. 160 feet) of the western fortress wall of Rusocastro, thus excavating its entire length which amounts to 68 meters (appr. 220 feet).

“This monumental fortification facility is the most large-scale element of fortress’s defensive system that has been exposed so far," says the Regional Museum of History in Bulgaria’s Black Sea city of Burgas which is in charge of the excavations.

An aerial shot of a newly discovered rectangular fortress tower on the western wall of the Rusocastro Fortress. Photos: Burgas Regional Museum of History

The archaeologists have found that the western fortress wall was 2.8 meters (9 feet) wide near the entrance of the Rusocastro Fortress, and reached a width of 4.2 meters (14 feet) in its northern end.

“Such a width of a medieval fortress [in Bulgaria] is known only from the Tsar’s citadels Tsarevets and Trapesitsa in the [late] medieval Bulgarian capital Tarnovgrad," the Museum emphasizes.

“The Burgas archaeologists in charge of the digs at the Rusocastro Fortress are still making sense of this fact," it adds.

The fortress wall of the Rusocastro Fortress lines the edges of a volcanic hill, and in some cases cracks in the volcanic rocks were filled up with stones, mortar, and soil in order to even the ground for the fortress wall foundations.

The archaeologists have now discovered that the original Early Byzantine fortress wall, which was built in the 6th century AD, was demolished almost down to its foundations during the reign of Tsar Ivan Asen II (r. 1218 – 1241), the most powerful ruler of the Second Bulgarian Empire (1185 – 1396/1422). Subsequently, the fortress wall was rebuilt but made about twice as thick.

“The wall was widened on the inside by up to 2.5 meters (8 feet), and then whole thing was built up as a single fortress wall," the Burgas Museum says.

Given the width of the 13th century foundations, the archaeologists estimate that the rebuilt walls of the Rusocastro Fortress were at least 12 meters (40 feet) tall.

On the outer side of the western wall, the archaeologists have discovered a previously unknown rectangular fortress tower which is 4.8 meters (16 feet) wide and 5.4 meters (18 feet) long.

Earlier this summer, the archaeologists discovered in the Rusocastro Fortress a hoard of seven silver coins minted in the Principality of Achaea, also known as Morea, a 13th century successor state of Byzantium founded by the Crusaders from the Fourth Crusade.

Shortly before that they had announced the discovery of an unknown 4th century AD fortress tower and a 14th century a Byzantine gold coin of Byzantine Emperors Andronicus II Palaeologus (r. 1282 – 1328) and Andronicus III Palaeologus (r. 1328 – 1341).

The newly found gold coin of Byzantine Emperors Andronicus II and Andronicus III from the Rusocastro Fortress is only partly preserved. Photo: Burgas Regional Museum of History

The tornese silver coins from the Principality of Achaea found in Bulgaria’s Rusocastro Fortress depict a cross and a tower of a Catholic cathedral. Photo: Burgas Regional Museum of History

Thanks to bones discovered during the 2017 excavations in Rusocastro, the archaeologists found out that the aurochs, the wild cattle which is the ancestor of today’s domestic cows, survived in today’s Bulgaria well into the 13th-14th century when it was still hunted for meat. It was previously thought to have gone extinct in the 12th century at the latest.

In November 2017, the Burgas Regional Museum of History announced the discovery of a huge water cistern plastered on the inside with pink waterproof mortar in the fortress, and in September 2017, it 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 excavations in Rusocastro have been led by archaeologist Milen Nikolov, Director of the Burgas Regional Museum of History. The 2018 digs have once again been funded by both Bulgaria’s Ministry of Culture, and the local authorities from Kameno Municipality.

Background Infonotes:

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 medieval Bulgarian Empire 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.



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