Friedenskirche (Church of Peace), formerly St. Nicolas Church/Reformed Church

The present Friedenskirche is Frankfurt's oldest church. However, a parish church dedicated to St. Nicholas, the patron saint of merchants, was mentioned at the site as early as 1226. Due to the southward expansion of the town, the establishment of the marketplace and the erection of both the Town Hall as well as the Church of St. Mary in the 2nd half of the 13th century, St. Nicholas' prior significance would gradually fade away. Finally, the wake of 16th century's Reformation saw the Church temporarily secularized and even used as a granary. As a result, the moniker Nikolaikirche was passed to the former Franciscan monastery church (nowadays' Carl Philipp Emanuel Bach Concert Hall), which would go on to serve as the parish church of the Evangelical Nikolai congregation - a community having up to more recent times consisted mainly of inhabitants of the pre-war Dammvorstadt, currently the Polish town of Słubice.

The old Nikolaikirche would have finally been reinstated as a place of worship  in the 17th century by both the Reformed and the French Reformed congregations (the Huguenots). Extensive reconstruction work carried out by Friedrich Adler between 1880 and 1894 introduced the church's current neo-Gothic form. In 1929 the de facto nameless Reformed Church was renamed Friedenskirche (Church of Peace). To this day the motives behind this particular choice of name remain unknown.