St. Johannis

St. Johannis stands in Mainz’s historical centre as the city’s oldest church, with more than 1,100 years of history. Its preserved walls show late Carolingian and early Ottonian architecture, shaped by later additions across many centuries.

The church began as a basilica in the seventh century and became Mainz’s first episcopal seat. Archbishop Hatto I consecrated it in 911, and the building served as the cathedral until 975, while three naves and a double choir shaped its east-west plan. Baroque and Art Deco refurbishments altered the interior, while reconstruction followed the 1942 air raid and reconsecration came in 1956.

Two arched windows and round windows open the east choir, while four arched windows break the clerestory above the narrow aisles. The present floor lies about 2.6 metres above Hatto’s level, with archaeological burials beneath it. In 2019, researchers opened a sarcophagus containing human remains and fragments of clothing and shoes, believed to belong to Archbishop Erkanbald, who died in 1021.