The Parochialkirche (literally the Reformed parochial church) is a Reformed church in the Klosterviertel neighbourhood of the Mitte borough in Berlin. The church, now a listed building, was built between 1695 and 1703, it is the oldest church in Berlin built as a Protestant place of worship. The church is now used and owned by the congregation of St. Mary's and St. Peter's, the merger of the parishes in the historical city center concluded on 23 September 2005. The congregation forms part of the Evangelical Church Berlin-Brandenburg-Silesian Upper Lusatia, a Protestant regional church body comprising Lutheran, Reformed and united Protestant congregations.
When the prince-electoral family of Brandenburg, the Berlin-based Hohenzollern, converted from Lutheranism to Calvinism (in German usually: Reformed Church; in English mostly: Presbyterian church) in 1613, all parish churches of Berlin, then under the patronage and advowson of the Lutheran city council, remained Lutheran. So only the Cölln Palace and Collegiate Church, the court church, was dedicated as a Reformed place of worship.
However, mainly by immigration the number of ordinary German-speaking Berliners of Reformed denomination, not employed at or belonging to the court, grew and a separate parochial church for them, as opposed to the Palace Reformed Church, was needed. Parochialkirche was the first and then only Reformed church for prevailingly ordinary Reformed congregants in Berlin, thus the undifferentiated name. As a Reformed church building Parochialkirche is not dedicated or even consecrated to any patron saint. The church was erected in Klosterstraße at the corner with Freier Fahrweg (renamed Parochialstraße in 1862), because the sites along Klosterstraße then formed a prince-electoral immunity district (kurfürstliche Freiheit), not under the legislation of the Lutheran city council, in order to circumvent the council's objection against its construction.