The first written reference to a castle in Murnau dates back to 1324. Ludwig the Bavarian, Emperor of the Holy Roman Empire of the German Nation from 1328, granted the castle as a fief. The residential tower that forms the core of the complex had, however, been built almost 100 years earlier, during the reign of the Wittelsbach Duke Otto II from 1231 to 1253. Based on archaeological excavations carried out between 1990 and 1992, the residential tower, located above the town at the western end of a rocky spur, was dated to 1233. The almost square building, which still has its full wall height, was constructed in a style that was common in southern Germany and Tyrol in the 13th and 14th centuries. The complex was continually expanded in the 16th and 17th centuries. A votive tablet from the 18th century in the parish church of St. Nicholas depicts the parts of the castle complex. At least since the High Middle Ages, there was a chapel in the southeastern area of the castle courtyard. As grave finds show, a cemetery was attached to it. The skeletons examined, probably from castle residents, perhaps also from local residents, were dated to the 12th to early 14th century. The abandonment of the cemetery in the 14th century may be related to the transfer of ownership of the Murnau market to the Ettal monastery and the Gothic church of St. Nicholas in 1330. The builder and first owner of the castle are not clearly known. From the second half of the 14th century, the monastery used it as the office and residence of its district judges, who exercised jurisdiction in the market and the surrounding area for the Ettal area. After secularization in 1803, when the monastery property in Germany became state property, the castle was auctioned off: the south wing went to the Murnau market, which set up rooms for the community school in it. The west wing was initially sold to private owners until it was also purchased by the Murnau magistrate in 1846. In 1862, the girls' school run by the Poor School Sisters moved in here. The Poor School Sisters had a chapel built on the second floor with high-quality mock architecture and stencil painting. The collection on James Loeb and "19th century painting" is now on display here. After a new school building for the girls' school was built east of the parish church in 1910/11, the south and west wings of the castle were used as a boys' school. The building has been used as a museum since July 1, 1993.