Around the year 60 B.C. King Burebista unified for the first time the Dacian tribes, who inhabited a territory roughly corresponding to present-day Romania. However, upon his death the kingdom disintegrated into different states that made the mistake to support Antony against Augustus (just as Burebista had previously supported Pompey against Caesar).
The disagreements between Dacians and Romans continued to occur over the years, with sporadic incursions and expeditions from one side and the other, in a tug-of-war that also had its moments of relative peace. But in the year 86 AD. the Dacians under their king Duras attacked the Roman border province of Moesia, south of the Danube. This forced the emperor Domitian to send the legions, even personally moving to the region to direct the operations.
But the Romans were ambushed and defeated in 87 AD. at the Battle of Tapae by the Dacian general Diurpaneus, who was immediately proclaimed king and assumed the name of Decebalus (the brave or more literally strong as ten (men) ). The Dacian resistance was based on six fortresses that had begun to rise in the previous century in the Orastia Mountains, in present-day Transylvania. Together they formed the defensive system used by Decebalus to hold off the Romans.
The six fortresses are Sarmizegetusa Regia, Costeşti-Cetăţuie, Costeşti-Blidaru, Piatra Roşie, Bănița and Căpâlna. All of them, very close, are in what is now Hunedoara County, except for Căpâlna, which is in Alba County. Precisely one of the peace conditions that the Dacians imposed on the Romans was the sending of Roman engineers and architects to build infrastructure and defenses in the six fortresses.
The walls of the fortresses were 3 meters thick and between 8 and 10 meters high. They were built using a method that mixed Greek and Roman techniques with others unique to the Dacians, and that is why today it is known as murus dacicus (dacian wall ). The Dacian wall consisted of two outer walls built of stone blocks cut into a rectangular parallelepiped, apparently without the use of mortar between them. The space between both walls was filled with gravel and crushed stone mixed and compacted with clay.
Through burnt wood beams the two walls were joined, giving rigidity to the structure. These beams were carved at the ends in a wedge shape and inserted perpendicular to both walls in each row of stone blocks. Although they resemble Hellenistic walls, they differ in that the Dacian walls do not have buttresses. Interestingly, the letters of the Greek alphabet have been found on some blocks of Dacian fortresses, engraved in groups of one, two or three characters.
Archaeological evidence suggests that the walls may have been topped by wooden palisades, rather than stone battlements, with the consequent disadvantage of being vulnerable to fire.
After the two wars undertaken by Trajan against the Dacians, the fortresses and the territory were conquered in 106 AD, a military garrison was established and the capital was moved to a newly founded city called Colonia Ulpia Traiana Augusta Dacica Sarmizegetusa (present-day Sarmizegetusa). All the fortresses were destroyed and rebuilt following the Roman model. Today they are declared a World Heritage Site.
Sarmizegetusa Regia
The main core of the defensive system was its capital Sarmizegetusa Regia (present-day Grădiștea de Munte), built on a mound above a cliff at an altitude of about 1,200 meters (about 40 kilometers from later Roman Sarmizegetusa). The fortress itself covered an area of 30,000 square meters and formed a quadrangle with strong walls stepped into five terraces.
Around it there were several sanctuaries, of which the most famous is the great sanctuary known as the Circular Calendar, and the houses and workshops of the citizens that stood on several dozen artificial terraces at the foot of the mountain. The noble dwellings even had running water, which came through ceramic pipes.
The access from the Mures Valley was defended and controlled by the fortresses of Costești – Cetățuie and Costești – Blidaru, as well as numerous towers located on both sides of the road. Other minor fortresses and probably several towers, not yet located, prevented access from the Cucuis and Sibisel valleys.
The western front was defended by the Piatra Roșie fortress and other minor enclosures. Other fortresses blocked routes into the heart of the Dacian kingdom. Only after overcoming all these obstacles did the attackers find themselves before the fortress of Sarmizegetusa.
Piatra Roșie
Built on a plateau at an altitude of 832 meters, it was equipped with a double fortification built in stone, with a quadrangular shape and 102 by 45 meters on each side. It had four defensive towers located at the corners of the enclosure, and a fifth in the center of the eastern side.
Access to the fortress was through the north-east corner tower, reached by a 3 meter wide stepped path paved with stone slabs. Inside the enclosure, the remains of a wooden construction were identified, whose stone bases have been fully preserved. Outside the enclosure, alignments of column bases were found, probable remains of a sanctuary.
For the water supply of the garrison stationed here there was a cavity cut directly into the rock in the northwest corner of the fortress. It controlled access to the capital from the Streiului Valley.
Costești – Blidaru
Also located on a ridge on a plateau at an altitude of 705 meters, it comprises two enclosures joined together, with six watchtowers. It is considered the strongest fortification in the entire system. It is the only one that could not be conquered in battle. Instead, the defenders surrendered due to exhaustion of resources after a long siege.
It had several towers and its walls reached 6 meters in height. The roofs of the barracks were used as combat platforms, on which war machines were installed.
Costești – Cetățuie
One of the oldest fortresses, it was the residence of some Geto-Dacian kings. Its fortification consisted of an earthen wall with a wide stockade of between 6 and 8 meters at the base, and a height of 2 meters and a half. It protected the top of the hill, the plateau and the terraces of the capital.
Today you can see the remains of two tower-houses with stone foundations and adobe elevations, as well as a monumental carved stone staircase, 3 meters wide, that led to one of these towers.
Bănița
It dates from the time of King Burebista, being rebuilt by Decebalus. It is located about 4 kilometers east of the town of the same name and at an altitude of 1,000 metres. It was arranged on terraces reinforced with stone walls, and inside there was a sanctuary similar to those of Sarmizegetusa, wooden buildings and a watchtower made of mud and wood.
The width of the defensive walls did not exceed 2 meters. These surrounded the enclosure only on the north and south sides, as the east and west sides were protected by the steep slopes of the mountain. It blocked access to Sarmizegetusa Regia from the south.
Căpâlna
Located on the outskirts of the town of the same name on a steep slope at an altitude of 687 meters, and arranged in terraces, with a tower almost 5 meters high raised on a platform carved into the rock.
The wall of the enclosure, of unequal thickness (between 1.5 and 2.5 meters) is preserved in most of its 280 meter perimeter. Inside were several buildings. On the highest terrace there was a wooden watchtower, a wooden building with a stone base, and next to the tower-residence a stone staircase and several wooden barracks.
Its strategic objective was to prevent access to the road that, starting from the current Polovragi, crossed the mountains through the Udele pass and descended to the Somes valley.