On February 3rd, 2004, a unique discovery was made on the premises of the Lesser Town building of the Faculty of Mathematics and Physics, Charles University in Prague. Believed to have been lost for 376 years even by many historians and archaeologists, St. Wenceslas Rotunda was finally discovered. A number of researchers attempted to locate the rotunda several times over the centuries, always with the conclusion that it must have disappeared without trace during the construction of the Jesuit Professed House. On the basis of an anonymous engraving depicting the invasion of the Lesser Town of Prague by the Passau forces in 1611, the rotunda was originally assumed to have been located in the western line of houses in the centre of Lesser Town Square. Today we already know that in reality, it was situated further to the east.