The group of fortresses and castles of Sureanu Mountains are also known under the name of the Dacian Fortresses of Orastie Mountains. They are situated within the central and Western part of the massif, most of them being concentrated in the basin of Gradiste river that flows out in Mures river. Here there are stone wall fortresses belonging to the Dacian fortifications system of Costesti-Cetatuie, Costesti – Blidaru, Piatra Rosie, Sarmizegetusa Regia, Banita and Capalna. They are placed on the outer edges of the Luncani Plateau – respectively of “Gornovita sculptural complex” or in their immediate neighbourhood – covering a surface area of 200 km2.
The Ancient ruins of Apa Orasului valley were known by the locals since very old times, as indicated by the frequency of the toponyms : Cetate, Cetatuie, Blidaru, Gradiste, while scholar people’s interest for them was raised later. The oldest written notice referring to them, was dated in the second half of the XVIth century when the presence of a visible foundations and stone wall town situated in the mountains was noticed, not far from Orastie town. After several centuries of silence, the findings of some gold coins, in 1784-1785 and particularly after 1802, drew the attention of the authorities and then, in 1837 and 1847 the ruins were visited by some educated people. Consequently, at the beginning of the XXth century Gabor Teglas stated that Gradistea Muncelului was the last refuge of Decebal. The systematic archaeological investigations performed by expert archaeologists started only in 1924 conducted by the professor, Dimitrie Mihail Teodorescu from the University of Cluj. Since then, they have been continued, with variable interruptions under the conduct of Constantin Daicoviciu, Hadrian Daicoviciu and Ioan Glodariu and thus, today, the location of all the significant vestiges is known even if only some of them have been investigated.
The zone of the Dacian capital was inhabited only sporadically before the II a. Chr. century. The oldest findings belong to the Upper Paleolithic and were located in Cioclovina cave. It was only after several millenniums that a community of the first – Indo-Europeans, the bearers of the Cotofeni culture, and ancestors of the later Thracians, settled there – they were the creators of the brilliant civilization of Bronze Age and first Iron Age.
Among the large Thracian community, their Northern branch, namely the Get-Dacians will be characterized by specific language elements and their belief in eternal life; a significant union of their tribes settled along the Middle Course of Mures river. It is sure that, by the end of the IInd a. Chr., century and early the following one, Costesti –Cetatuie was its main centre. The economic flourishing, implicitly the political and military power of this formation was based on the wealthy Mures valley with its excellent farming lands, on the Metaliferi Mountains with gold deposits and Sureanu Mountains with iron ore deposits outcropping at surface.
Some time before the year 82 a. Chr. Burebista took the power and succeed in reuniting under his leadership most o the Dacian – Getts tribe unions and to establish a vast kingdom from the Balkans Mountains to the Forestry Carpathians and from Morava (Czech Republic of today) to the banks of Nipru, at Boristene and Olbia.
It was also him who included in his kingdom the older fortifications and built new ones, too. They watched the main commercial routes of Dacia and closed those which crossed the Carpathians by fortifications located at the entry and exit of the mountains. Burebista successors continued the construction of fortifications