Ducal Rotunda of the Virgin Mary and St Catherine, Romanesque rotunda in Znojmo, Czech Republic

The Ducal Rotunda is a cylindrical Romanesque chapel with an eastern apse, built on a raised rocky spur and entered by a staircase. Its walls are laid in irregular dark rubble stone, carefully coursed, and small Romanesque windows light the interior. The nave walls carry the 1134 frescoes, including a painted arch framing a white horse and rider.

The rotunda was probably built in the first half of the 12th century as a castle chapel within Znojmo Castle, during the reign of Prince Konrad II of Znojmo. In 1134, on the occasion of his wedding to Maria of Serbia, Konrad commissioned the frescoes and had the chapel's dedication changed from the Virgin Mary to St Catherine of Alexandria, as recorded in a Latin inscription discovered in 1947.

The frescoes depict Přemyslid rulers alongside the donor couple Konrad II of Znojmo and Mary of Serbia, painted for their 1134 wedding. The legendary ancestor Přemysl the Ploughman and Vratislaus I, the first King of Bohemia, are the two figures historians agree on; the rest are disputed.

The rotunda stands on a raised rock spur inside the Přemyslid castle grounds, reached by a staircase, so the visit involves steps. The interior is lit only by small Romanesque windows. The building is a national cultural monument, and the frescoes have been restored repeatedly, most recently in 1971.

The frescoes were not left untouched: they were restored in 1891–93, 1938, 1947–49, 1969 and 1971. A Latin inscription scratched into the plaster, found by František Fišer in 1947, records that Konrad II changed the chapel's dedication to St Catherine in 1134.