Dominating the Zürich skyline, the twin towers of Grossmünster are the most prominent landmark in the city. It is the city's largest church (hence the name), built between 1090 AD and 1220 AD, in a Romanesque style, as a replacement to an older church. The previous church had been built by Charlemagne, supposedly over the tombs of the patron saints of the city, Felix and Regula, to whom Grossmünster is dedicated. In the 16th century, Grossmünster led the Swiss-German Reformation movement and it was converted from Catholicism to Protestantism, losing in the process most of its images, icons and other rich ornamentation, in accordance with the strict rules of the Reformation. Nevertheless, some fine Romanesque details still decorate both the exterior and the interior (where photography is not permitted). Its two towers, were added in the 15th century, originally topped with wooden structures, but a fire in 1781 caused partial destruction