The rotunda was built in the first quarter of the 11th century in the area of the city castle. Partial reconstruction took place around 1435, when the walls of the nave were raised and the second floor was created. After this reconstruction, the rotunda was incorporated into the defense system as a watchtower, and the lower space was still used as a chapel. At the end of the 16th and at the beginning of the 17th century, the Skalica burned twice and the fire also damaged the rotunda. Then after 1650 it was repaired, but unfortunately it was rebuilt in the spirit of the baroque. It lost defensive function, received a new roof, and the windows were enlarged. During the Second World War in 1945, it was destroyed by a bomb explosion. During later reconstruction in 1949, external plaster was removed and original romanesque and gothic elements were shown. Post-war repair ended in 1954.
The romanesque rotunda consists of a cylindrical nave and semi-circular apse from the north-east. It has an extremely thick wall: from 130 to 140 cm. The inner diameter of the nave is 540 cm. The apse opens onto the space of the nave with a straight edge, without distinguishing of the arch. On the west side, just under the roof is a gothic portal connecting the rotunda with fortifications. The second floor of the rotunda was added in the first half of the fifteenth century, during the transformation of the rotunda into a tower of town fortifications.
Website apsida.sk, Skalica.