“Old St. Martin’s Cathedral” must have been located where St. John’s stands today. Around 900, Archbishop Hatto (891-913) had the building constructed which was later connected to Willigis’s cathedral by a parvis, a colonnade. This is one of the few known basilicas dating from Carolingian times with its walls still intact. In the 14th century a Gothic west chancel was added. Since 1828, the church, which was previously used by the collegiate foundations of St. John and St. Victor, has been Protestant.