Under Karl the Great it was raised to an imperial palace and the last Carolingian Emperor Arnulf of Carinthia had a palace chapel built here in 898. Already before the year 1030, the Emperor Henry II erected the parish Ranshofen and had a parish church built. Emperor Conrad II acknowledged this parish in 1040.
During the War of Succession of Landshut (1504/05), both church and monastery were badly damaged. Additional working quarters and a new monastery section were built in the first half of the 17th century including prelate office, convent and library.
On the occasion of the 800th anniversary of the Palace Chapel, both church and monastery were baroquised in the year 1698 and this is how the church interior and the other buildings present themselves to visitors to this day.
Only a few years after the inclusion of the Inn District to Austria in 1779, the parish church St. Michael was closed and razed in 1798. Its stones were used for improvements on Braunau´s enormous bastions.
In 1810, the Inn District was temporarily joined on to Bavaria by the grace of Napoleon and only one year later (1811), the Monastery Ranshofen was disbanded at the order of Minister Montgelas. The monastery building was then secularised and turned into a palace.
In 1938, the "Vereinigte Aluminiumwerke Berlin" acquired the Jewish possession and established a modern aluminium plant.