Faculty of Mathematics, Physics
and Informatics
Comenius University Bratislava

St. George’s Rotunda in Nitrianska Blatnica

International consortium of radiocarbon laboratories dated St. George’s Rotunda in Nitrianska Blatnica

10. 03. 2022 20.48 hod.
By: Pavel Povinec

Radiocarbon laboratory of the Department of Nuclear Physics and Biophysics (DNPB) of the Faculty of Mathematics, Physics and Informatics of the Comenius University determined that the St. George’s Rotunda in Nitrianska Blatnica was probably built in the years 830 ± 30 AD, i. e., the Rotunda could have been constructed before the arrival of Constantine (St. Cyril) and St. Methodius to Great Moravia (< 863 AD). As archeological investigations indicated that the Rotunda could have been constructed later, and also because this result attracted international interest, an international consortium of radiocarbon laboratories from USA (University of Arizona in Tucson, and University of Georgia in Athens), Switzerland (ETH, Zurich), as well as from neighboring countries (to contradict possible doubts) – from Austria (University of Vienna), from Czechia (Institute of Nuclear Physics of the Czech Academy of Sciences in Prague), from Hungary (Institute for Nuclear Research of the Hungarian Academy of Sciences in Debrecen), and also from DNPB. The objective of the international consortium was to verify the age of the Rotunda by analyzing all samples which were found during its recent restauration. As the Rotunda was during its long history several times seriously damaged, and therefore repeatedly reconstructed, its present Baroque look did not suggest that it could be an old stone building.

Radiocarbon analysis of 20 samples collected from the Rotunda walls (wood, charcoal, mortar and plaster) showed good agreement between laboratories analyzing the same as well different samples. Elaboration of results (using the newest radiocarbon calibration curve) showed that the consortium results have been consistent with the previous DNPB results. The obtained age of the Rotunda suggests that it is probably the oldest standing sacral building not only on the territory of Slovakia, but also in the eastern part of the Central Europe (east of Salzburg). 

This discovery suggests that Christianity on the territory of Slovakia (more precisely in the Nitra principality) was already spread during the reigning of Prince Pribina. 

P. P. Povinec, A. Cherkinsky, J. Dorica, I. Hajdas, A. J. T. Jull, I. Kontuľ, M. Molnár, I. Svetlik, E. M. Wild: Radiocarbon dating of St. George’s Rotunda in Nitrianska Blatnica (Slovakia): International Consortium results. Radiocarbon, Vol. 63, Nr. 3, 2021, p. 953-976.