Burgas region takes an important place in the history of Bulgarian lands especially during the Middle Ages. Goths, Huns, Avars and Slavs traversed here during their devastating march to the land of Southern Thrace in the 4th-7th century. Due these events, numerous settlements from Roman times situated west of the Black Sea, ceased to exist leaving only the major urban centres Mesambria, Anhialo, Sozopol and Debelt.
Unable to stop the barbarian tribes with the fortifications along Danube, at the end of the 5th - beginning of the 6th century, the Byzantine Empire created a spectacular system of fortresses and walls along the ridge of the East Balkan Mountains. Fortified are primarily important roads in the passes Emine, Diulinski and Aitos. This policy led to the construction of large fortresses such as the fortress in nowadays district Kraimorie, Burgas, location also of the old Roman road station Pudizo; fortresses found near the present villages Rusokastro, Polski izvor, Vratitsa, Karanovo, Bulgarovo, Malka polyana, Sadievo, Dryankovets and others. After the establishment of the Bulgarian state in 681, Burgas region is an arena of all major battles between the Bulgarian rulers and the Byzantine Empire. The victories of Khan Tervel near Anhialo in 708 and of Khan Kardam in fortress Markeli (next to the modern city Karnobat) in 792, attested the prestige of the
Bulgarian state and the famous victories of Khan Krum from the beginning of the 9th century led to the construction of a frontier bank called Erkesia - a large border earth facility along the southern border of Bulgaria. The custom between Bulgaria and Byzantium was placed in Debelt, at the beginning of Erkesiata frontier bank; hence here it was delivered the annual tax by the emperors of Constantinople to the Bulgarian khans and tsars.
The peak of Bulgarian supremacy over the Byzantine Empire was the Battle of Aheloy in 917, when the Tsar Simeon completely destroyed the Byzantine army.
After the fall of the Bulgarian capital Preslav in the hands of Prince Svetoslav of Russia in 969 and expulsion of the Russians by Emperor John I Tzimiskes in 971, the lands today South-eastern Bulgaria were annexed once again to Byzantium. During this period the development of coastal cities has increased, as well as of those further inland - Aquae Kalide (in today's Burgas district Banevo) Rusokastro, Karnobat fortress.
With the rebellion of the brothers Peter and Asen in 1185 began the regain of Bulgarian lands south of the Balkan Mountains. By 1202 -1205, the whole of today southeast Bulgaria was under the authority of the Bulgarian tsars. This remained until 1263 - 1264, when, in turn, the renewed Byzantine Empire in a series of marches rejoined with the coastal cities. The crisis in the Bulgarian state ended with the reign of Tsar Theodore Svetoslav (1300 - 1322). His policy was to gain back the southern coast as Bulgarian territory. In 1304, near the present-day lake Mandra, Tsar Theodore Svetoslav and his uncle, Despot Eltimir Terter, defeated the Byzantine army at the Battle of River Skafida and regained power over the coastal cities - an act officially recognized in 1308. This remained until 1330 when taking advantage of the death of Tsar Mihail Shishman, the Byzantine Emperor Andronicus III re-conquered the lands south of the Balkan Mountains. The new Bulgarian Tsar Ivan Alexander reacted immediately to this aggression. Mobilizing all his army, aided by Tatar mercenaries, he defeated the Byzantines at the Battle of Rusokastro on 18.07.1332. Almost to the end of his reign the southern Black Sea coast remained part of the Bulgarian state.
One of the Foros towers near Poda.
The study of the Middle Age in Burgas region began in the middle of the last century, when during surveys in the ancient cities of Apollonia, Mesambria, Debelt and Anhialo appeared many artefacts and complexes from the 7th-15th century. In the recent years, Burgas Museum conducts yearly research in the strongholds at Foros Peninsula, nowadays district Kraimorie, Burgas. This area was marked as Port Poros on Pietro Visconti's chart from 1321. In 2008 at the western end of the peninsula, team of archaeologists discovered a hitherto unknown fortress whose area exceeds 15 hectares and another fortress at Cape Kabata on the northeast coast of the peninsula Foros as well as many remains of Late Antique and early Byzantine constructions in the northern part of the peninsula. In 2009 Burgas Museum conducted excavations at the tower in the area Poda, where despite strong destruction caused by the modern city development, there were found numerous artefacts from the 4th-15th century as well as foundations of the massive building from the 8th – 14th century. Тhe east bank of Lake Mandra, south of the tower, is the location of Skafida - а large stronghold with port known from medieval chroniclers at the end of the 13th - 14th century. Skafida is also marked as a port in Visconti's chart and in anonymous Italian port chart from the 15th century.
On the territory of present-day city of Burgas in the second half of the 8th century there was a small fortress by the name Pyrgos.
Information about it has been given in a work of the Byzantine poet Manuel Phil, who in his poem dedicated to Commander Michael Tarhaniot indicates that in 1263-1264 the Byzantines conquered the Bulgarians strongholds Skafida, Kastritsium and Pyrgos.
View of the Fortress Rusokastro.
Since 2006 experts from Burgas Museum have been researching Fortress Rusokastro, 2 km. away from the present village Rusokastro.
The result showed that Rusokastro is the largest fortress in today's south-eastern Bulgaria, with an area of 50 acres, reinforced with double fort walls and citadel. In 2009 the fortress water supply facility was uncovered; it consists of a secret passage fortified with walls 100 meters in length, leading from the castle to the water tower-well, supplying water from the river Rusokastrenska. Found were nearly 20 outright ceramic vessels, coins, stamps, jewellery and many other artefacts from the 6th - 14th century, which can be seen in the Archaeological Exposition of Burgas Museum.
708 – Battle of Anhialo. Khan Tervel defeated the Byzantine Emperor Justinian II.
917 - Battle of the River Aheloy. Tsar Simeon the Great defeated and completely destroyed the Byzantine army.
1304 - Battle of the River Skafida (near the present village Dimchevo). Tsar Theodore Svetoslav and despot Eltimir Terter defeated the Byzantines and return the South Black Sea coast in Bulgarian borders.
1332 - Battle of Rusokastro. Tsar Ivan Alexander defeated the Byzantine army and besieged the shattered armies led by Emperor Andronikos III
Palaiologos in the fortress Rusokastro. Hereafter Andronicus III finally admitted the Bulgarian possession over the South Black Sea coast.