The most important of these six citadels that Decebalus used as a defensive ring was Sarmizegetusa Regia, a name which has been interpreted to mean “High Citadel” or “Cliff Citadel”, a theory that seems consistent with its location, on top of a 1200 m high cliff in the Gradistea Muncelului village. It stood as administrative and religious capital of Dacia and most prominent of its urban settlements, extending over an area of some 30,000 square meters laid out on five terraces. The defensive walls, made of massive stone blocks, were 3 m thick and 4 or 5 m high, shaping a rather unusual hexagon with asymmetric sides. The settlement included several large sanctuaries, two circular ones and seven or eight rectangular ones, situated at about 100 m off the eastern gate of the fortress and connected to it through a paved road.
The western flank of Sarmizegetusa was guarded by the Luncani-Piatra Rosie citadel, which owes its name to the fact that its walls were built of red stone, as opposed to the white limestone used for the rest of the fortresses. It was built in the I century B.C. and it had five towers and one gate, all of which were destroyed by the Romans in 106 A.D.
The oddly shaped fortress of Costesti-Blidaru was the strongest of the six Dacian citadels, situated on a 6000 square meters plateau at an altitude of 750 m. It was actually made of two fortified yards: the first one had four corner towers and a fifth stronghold inside, with the only entrance strategically placed so as to prevent the enemy from fully deploying their armies, forcing them to go around the wall and expose their flank; the second one improved the security of the fortress by adding another two strong towers.
Slightly lower in terms of altitude, at 514 m, the Costesti-Cetatuie Dacian citadel enjoyed a complex defense system, complete with earth-works, palisades, and double walls that were at least 3 or 4 meters high and 3 m thick. The space between the two walls was filled with dirt, clay, raw stones, and the like, with the entire mix being supported by wooden beams. The strategic role of this citadel was to guard the road to Sarmizegetusa.
A less effective defense system was used at the Capalna fortress, which had two terraces surrounded by an elliptical wall and a shallow moat. Most of the buildings inside were made of wood and were reduced to ashes when the Romans burnt the entire citadel down in 106 A.D. Finally, the sixth Dacian citadel was located at Banita, its purpose being that of defending the southern flank of Sarmizegetusa. It was protected by walls, towers, and earth-works, but the only remains still visible today are fragments of the walls.
Located in Orastioara de Sus village, Hunedoara, in Southern Transylvania, Sarmizegetusa Regia is an ancient fortress that was once the most important military, religious and political centre of Dacia, before the Roman conquest in 106 AD. Dacians are thought to be the ancestors of the Romanians and were documented in 300 BC when Alexander the Great tried to conquer what was then a state founded on a military democracy on the lower Danube. As Emperor Trajan conquered the Dacians, Dacia was soon under an economic and cultural assimilation, with Romans crossing the border and cohabiting with the Dacians.