St. John's Church, Mainz
St. John's Church (in German Johanniskirche) is located beneath Mainz Cathedral in the historical center of Mainz, Germany. This 1100-year-old church was the first episcopal see of the Bishop of Mainz. It is the oldest church in Mainz, the oldest cathedral in the Germany of today and the only preserved cathedral building from late Carolingian and early Ottonian time in Germany.St. John's Church is predominantly Carolingian in style, but later exterior additions over many centuries have resulted in the appearance of various architectural influences seen today. It comprises three naves and stands under the patronage of John the Baptist today.