EN
Rotary mills or their stone parts, i. e. quern stones and millstones, occur only exceptionally at medieval and post-medieval castles – unlike the rural environment. The quern stone discovered in 2018 in the northern part of the castle courtyard near the eastern wall of Oponice castle’s barbacan (Topoľčany district) is one of such exemplars. By its shape and size, we can assume that originally it was a La Tène quern. It was secondarily adapted and used as the rotating part of a hand mill probably during the castle’s existence. The objective of our article is to explain the function of the unusual quern stone at Oponice castle and use of grinding tools at medieval and post-medieval castles.