The oldest traces of settlements on the Kostolec hill date back to the early Stone Age (22,000 BC) and the late Stone Age (2000 BC) In the Bronze Age (1100 BC), there was here a significant hillfort of Velatic-Baierdorf culture settlement. The traces of settlements from Roman times (2nd to 3rd century AD) are also noteworthy. Kostolec played a key role during the Great Moravia in the 9th – early 10th century. A defensive, early feudal fortress was erected here with residential buildings, a small church and economic outbuildings. It was a center of power and administration, to whom was subject agricultural and craft settlement in the area. It also guarded the nearby ford on the river. The destruction most probably occurred around 940-970, probably as a result of the Hungarian invasion. After the disappearance of the hillfort, from the second half of the tenth century to the fourteenth century, there was a burial place of several nearby settlements, the rotunda probably still functioned. In the fifteenth century, several economic buildings were built here, and the hill from time to time was used for defensive purposes.
The Great Moravian stronghold was protected by a wooden oak palisade, and the interior of the courtyard was divided by additional stockades. There were wooden residential and commercial buildings, a stone rotunda and a cemetery. Rotunda was a building on the plan of the circle with a small apse. It has an internal diameter of 730 cm, and the apse had diameter 365 cm. In general, the church was over 12 meters long and almost 9 meters wide. The walls could reach a height of about seven meters. They were whitewashed and decorated with wall paintings in the interior.
There is a partially reconstructed palisade fortification with a gate and a brick outline of the foundations of the pre-Romanesque rotunda in the hillfort. There is also attached a model of a watchtower and a burial place.
Website apsida.sk, Ducové – Kostolec.
Website wikipedia.org, Ducové.