The Rotunda of the Holy Cross is the oldest Romanesque rotunda in Prague. It was built in the 11th century. The first mention of the Rotunda of the Holy Cross is from 1365, but it was probably built already at the end of the 11th century. It is a small simple building with a rounded nave and an apse. A lantern at the cupola has a gilt cross, a crescent moon and an eight-pointed star at the top.
Rotunda of the Holy Cross was probably a private chapel belonging to some of the mansions in Prague Old Town. There used to be a parsonage nearby and a cemetery around.
Dominicans gained the rotunda in 1625. Emperor Joseph II. abolished the chapel in 1784, as well as many other churches, and it became a private storage. It was planned to demolish the rotunda in 1860 because of building a new house at the place, but it was finally saved.
There are remains of Gothic wall paintings from 14 th century inside. The most valuable Gothic fresco is the “Three Magi veneration”. There are also some remains of tombstones from 13 th century.
The legend about the origin of the rotunda says, that there used to be a lake at the place originally. A crucified girl, punished for her Christian belief, was thrown there with her cross. The cross reared up during a storm, which was regarded as a God´s sign. A large dozy cross was really found in the foundations of the rotunda, when it was restored.
References:The Church of St Donatus name refers to Donatus of Zadar, who began construction on this church in the 9th century and ended it on the northeastern part of the Roman forum. It is the largest Pre-Romanesque building in Croatia.
The beginning of the building of the church was placed to the second half of the 8th century, and it is supposed to have been completed in the 9th century. The Zadar bishop and diplomat Donat (8th and 9th centuries) is credited with the building of the church. He led the representations of the Dalmatian cities to Constantinople and Charles the Great, which is why this church bears slight resemblance to Charlemagne's court chapels, especially the one in Aachen, and also to the Basilica of San Vitale in Ravenna. It belongs to the Pre-Romanesque architectural period.
The circular church, formerly domed, is 27 m high and is characterised by simplicity and technical primitivism.