The ruins of the Late Antiquity / Late Roman and Early Byzantine fortress and settlement Storgosia, also known as Dianensium in the Antiquity, and as Pleun in the Middle Ages, are located in the Kaylaka Park in the northern Bulgarian city of Pleven.
The Kaylaka Park itself (the name stems from Ottoman Turkish, and means “a rocky place"), a beautiful gorge of the Tuchenitsa River, features archaeological remains indicating civilized life as early as the 5th millennium BC, as well as traces of Ancient Thrace.
The Antiquity settlement Storgosia (Dianensium) was first started as a Roman road station on the road connecting the major Roman city of Ulpia Oescus (located near today’s town of Gigen) on the Danube, and Philipopolis (today’s city of Plovdiv in Southern Bulgaria). The Roman road station was first located in what is today’s downtown of Pleven on the spot of Ancient Thracian settlements from the Bronze Age and the Iron Age.
Detachments from the Italian First Legion (Legio I Italica) based in the large Ancient Roman city of Novae on the Danube River, today’s town of Svishtov, were stationed at Storgosia (Dianesium), with the road station gradually attracting settlers from around the region.
The Gothic invasions into the Balkan territories of the Roman Empire, which began in 238 AD, ushering into several centuries of barbarian invasions, forced the Roman authorities to adopt measures to protect the local population.
This led the population of the road station to move to the site of today’s Kaylaka Park, about 2.5 km to the south, because of its natural defenses. The new settlement was built on a high plateau on the left bank of the Tuchenitsa River.
The fortress wall of Storgosia was built at the beginning of the 4th century AD. The wall was 2.2 meters wide, and encompassed a settlement with an area of 31 decares (app. 7.5 acres); it was made of stones and white mortar.
The archaeological excavations have revealed that Storgosia had two gates, three fortress towers, homes, a public horreum (i.e. a granary), administrative and military buildings, and a large Early Christian basilica, which was 45.2 meters long and 22.2 meters wide.
According to some experts, this may have been the second largest (Early) Christian temple in the medieval Bulgarian Empire (in particular in the First Bulgarian Empire (632/680-1018 AD), after the 9th century Great Basilica in the early capital Pliska (680-893 AD) which was 102.5 meters long and 30 meters wide. (The Round Church, also known as the Golden Church, in the other early capital Veliki Preslav (Great Preslav) (893-970 AD) was a bit smaller – 40 meters long and 21 meters wide.)
The archaeological excavations of Storgosia and its necropolis have discovered artifacts such as ceramic items, weapons, and coins, leading the archaeologists to conclude that the Late Roman and Early Byzantine fortress existed until the end of the 6th century AD. It is believed that the ancient city of Storgosia was destroyed in the barbarian invasions of the Slavs and Avars which started in the 6th century and ended in the middle of the 7th century.
At the time of the medieval Bulgarian Empire, the site of the Storgosia Fortress was turned into the medieval city of Pleun (today’s Pleven), which existed throughout the entire Middle Ages as a strong fortress with developed crafts and trade.
Folk legends say it was connected with the last days of the last holder of the Tarnovgrad (Veliko Tarnovo) throne of the Second Bulgarian Empire (1185-1396 AD), Tsar Ivan Shishman (r. 1371-1395 AD).
In 2013, Pleven Municipality completed a project financed with about BGN 5 million (app. EUR 2.5 million) in EU funding for the restoration of the Storgosia Fortress, the Pleven Panorama, and the Victory Monument and Bridge on the Vit River (the latter two monuments are connected with the Russian-Turkish War of 1877-1878 which brought about Bulgaria’s National Liberation from the Ottoman Empire).
The restoration project has been criticized for violations in its public tender and it has been claimed that it has caused damage to the original ancient and medieval ruins causing concern that it might end up as one of Bulgaria’s notorious botched archaeological restorations.