Does the history of the famous Frauenwörth Abbey need to be rewritten? During radar surveys on Fraueninsel in Lake Chiemsee, archaeologists came across the remains of an unknown sacred building from the Middle Ages. The Romanesque building was impressive in size and unusually designed. Experts say it may have been a forgotten place of worship for Blessed Irmengard.
Idyllically located in Lake Chiemsee, the Fraueninsel with its old abbey is one of the most famous sights in the Bavarian foothills of the Alps. The history and structural development on the 620 meter long and 300 meter wide island is actually considered to be well researched: The development began around 782 AD with the founding of the Benedictine monastery in Frauenwörth by Duke Tassilo III. A gate hall remains from this Carolingian era. Most of the other buildings in today’s complex come from later expansions and structural redesigns of the monastery.
A second find under the first
At the beginning of the current discovery story there was research into a building in the complex, which has also disappeared today but was already known. It was the Church of St. Martin, first documented in 1393, of which there are historical images as well as mentions. According to the information, it was located on the highest point of the island, near the “Tassilo tree” that still exists today and is probably over 1000 years old. According to historical sources, this church was demolished in 1803 as part of secularization. In order to accurately record its former location, investigations were carried out in the relevant area using ground radar in the summer of 2023.
The archaeologists from the Bavarian State Office for Monument Preservation (BLfD) actually came across the foundations of St. Martin at a depth of 50 to 70 centimeters. The floor plan identified matched a view of the elongated church building in an engraving from 1701. But then, surprisingly, foundation walls that lay a little deeper underground became apparent. They obviously come from a previous building, of which, surprisingly, nothing has survived – neither in writings nor on historical maps.
As the BLfD reports, according to the radar data it is clearly a building in the form of a so-called central building. In contrast to the usual elongated shapes of churches, they have main axes of equal length. In the current case, what was left was an octagonal building with an ambulatory formed by eight supports and four extensions arranged in a cross shape. Overall, the structure had a considerable diameter of almost 20 meters, according to the data.
An unusual central building
As the experts emphasize, it is an unusual architectural design: “In Bavaria, octagonal central buildings with an inner colonnade have only been archaeologically proven with St. Andreas in Bamberg, around 1050, and St. Gallus in Würzburg, around 1130. “So we’re talking about an absolute rarity here,” says Mathias Pfeil from the BLfD. “Central buildings are generally rare in pre-Romanesque and Romanesque sacred architecture north of the Alps. This design is often interpreted as a reference to the Palatinate Chapel in Aachen or as an imitation of the Church of the Holy Sepulcher in Jerusalem,” says Pfeil.
But how can the find on Fraueninsel be classified historically? Experts say there may be a connection with the veneration of Blessed Irmengard. Charlemagne’s great-granddaughter was abbess of Frauenwörth until 866 and was also buried in the church of the imperial monastery. Between 1001 and 1020 her grave was apparently opened to remove relics. At the same time, there were also significant structural changes to the monastery complex. Perhaps the building now discovered was created in this context as an additional memorial building to venerate Irmengard: based on the design of the Jerusalem Church of the Holy Sepulcher, it could have served as a destination for pilgrims, according to one possible explanation.
However, there are still some questions to be answered, say the experts. “It remains exciting to see how science will classify this find historically,” says the Bavarian Minister for Science and Art Markus Blume. However, it still seems unclear how things will continue. At least there is already debate about visualizing the floor plan in the form of plants next summer and thus making it tangible, writes the BLfD.