Cathedral of St. Maria and Markus

The oldest church of the island is the cathedral St. Maria and Markus, the former monestary church (monestary foundation 724). The simple timber construction of the monastery founder Pirmin was too small after only a few decades and was replaced by a 40 m long stone building in the 8th century. North of it, opposite of the still visible convent buildings today, was a cloister and a two-storeyed monk's house. Counting 134 monks by the middle of the 9th century, these buildings were soon extended as well.

While this monastery is preserved only in subterranean traces, we can understand the development stages of the abbey church to this day. Thus, the eastern transept and the crossing arch come from the consecrated in 816 three-aisle cross basilica, which was built by Abbot Heito I. While Heito's crossing building remained unchanged for a long time, the western part of the abbey church was rebuilt several times. The western part received its current appearance under Abbot Berno. It was consecrated before his death in 1048 in the presence of Emperor Henry III.

After the abbey's decline a regular monastic life reemerges with Abbot Friedrich von Wartenberg (1427-1435). He started the construction of the Gothic choir in the east of the cathedral. The construction was finalized only in 1555 when final touches were made on its painting. After the incorporation into the diocese of Constance in 1540, the monastery continued as a priory. Prince-Bishop Jakob Fugger built new convent buildings to the south of the cathedral from 1605 to 1610.

After the completion of the plant, the "Old Monastery" on the north side was demolished. The monastery was dissolved in 1757. Today Fugger's "new" convent buildings house the parish and municipial administration. Reichenauer Wine is pressed in its extensive cellar by the winegrower association. Countless reliquary shrines and other cultural objects from the 5th to 18th century are exhibited in the cathedral's treasury.