The church is Kraków's best preserved Romanesque building, raised in the second half of the 11th century. The façade of the three-aisled church is crowned with two towers, octagonal in their upper parts, and quadrilateral in the lower run. They are both covered with baroque steeples. The lack of windows in the lower sections and embrasures is a testimony to the former defensive character of the building. It was a part of the motte of Wawel Castle, known as Okół. In case of danger, it provided shelter for the locals, as during the Tatar raid in 1241.The upper storeys of the towers are decorated with typical Romanesque windows known as biforia. Individual windows ending in semicircles are present on the lower floors. Yet another type of Romanesque windows, divided by two columns (triforium), decorate the upper part of the façade of the church in Grodzka St. The construction of the roof marks the distinction between the nave and the chancel enclosed from the east with a much lower apse. The entrance from Grodzka Street is surrounded by a low wall with a model showing a Romanesque biforium. Adjacent to the church are the buildings of the convent of the Order of Poor Clares, who came here in the first quarter of the 14th century. To this day, the nuns observe the austere Rule of St Clare, and do not allow strangers into their enclosure.