The Barockbasilika (Baroque Basilica) St. Mang, which used to serve as the abbey church, was built by the German architect
Johann Jakob Herkomer. It took him 16 years to complete. He succeeded in turning the medieval Basilica into a Baroque Church based on Venetian models that was intended to be an architectural symbol of the veneration of Saint Magnus. The entire church represents an enormous reliquary.
The basilica was used as an architectural model for St. Jacobs Cathedral in Innsbruck, Tyrol (Austria).
In 1837 the former abbey church was transferred as a gift to the parish of Füssen.