Sharp Rock was an important Celtic hillfort, more specifically, the population from the Púchov culture. A settlement near the Sharp Rock gave the hillfort water, food and work, and on the other hand, the population could get into the fortifications in time of danger and find shelter from enemies. Its favorable location was rediscovered in the 9th century by the Slavs, who renovated part of the fortifications and built new dwellings. The hillfort survived the Hungarian invasion and was settled until the 12th/13th century.
The stronghold was erected on a high rock massif, on the south side protected by rocky walls of 50 to 70 meters in height. In the late La Tène period, access to Sharp Rock ran from the west, next on the northern slope of the hill and further through the gate protected by stone – wooden fortifications. Behind the gate there was a lower courtyard with a relatively sloping area in the north. The entrance to the central courtyard was made possible by the second gate from the east. A defensive wall with a palisade reached a height of 3,5 meters. The main buildings of the hillfort were in the third, highest part, on the top of the hill and were protected by a separate defensive wall. This part was the only one used in the later Slavic period of the hillfort’s existence. The technique of making fortifications, which were than only made of wood, has also changed.
Website hradiska.sk, Vyšný Kubín – Ostra Skala.