The establishment of the modern-day protestant parish church, St. Johannis, goes back to 911-931. In 1139 the parish and the church are first mentioned in documents. The extension of the church to a gothic hall church with a nave and two side aisles began in 1410-1413. In the 18th century the interior of the church was changed to baroque style.
Well worth seeing is the northern side altar, a masterpiece of altar architecture from the Renaissance (Flötner Altar) and the royal burial vault from 1660 underneath the choir (can be found today in St. Gumbertus). The small Güll fountain found on the exterior wall in Martin-Luther Place reminds of a motif from the poem “Der Pflaumenregen” (The Plum Rain) by the poet Friedrich Wilhelm Güll (1812-1879). His place of birth can be found opposite the small fountain on the south side of Martin-Luther Place.