The castle was built around 1360 to 1371 by the Counts of Katzenelnbogen. The reason was probably the direct neighborhood of Maus Castle in Electorate of Trier, which had been under construction since 1356. Furthermore, the castle, together with Rheinfels Castle on the other side of the Rhine, formed a customs barrier and thus strengthened the network of castles that the Lords of Katzenelnbogen controlled in southwest Germany.
The male line of the Katzenelnbogen family died out in 1479. The count's office - and with it the castle - went to the Landgraves of Hesse, as Landgrave Heinrich III. of Hesse-Marburg had married the daughter of the last Count of Katzenelnbogen. As a result, Katz Castle, like Rheinfels Castle, became a bone of contention in inheritance disputes between the Hesse-Kassel and Hesse-Darmstadt lines. It was besieged and partially destroyed in 1626 and 1647. During the dispute it was reinforced several times with fortifications and gun emplacements.
In 1692 the castle suffered destruction again during the War of the Palatinate Succession during the siege of Rheinfels Castle by the conquering armies of Louis XIV. It was conquered by the French in 1758 during the Seven Years' War and returned in 1763. Napoleon finally had the previously undestroyed castle complex blown up in 1806, as did Gutenfels Castle above Kaub.
In 1816 the castle ruins came to the Duchy of Nassau, passed through various private hands over the course of the 19th century and were finally acquired in 1896 by the then district administrator of the St. Goarshausen district, Ferdinand Berg. He had the castle rebuilt as a residence according to plans by the Cologne architectural firm Schreiterer & Below, based on the medieval structure and in keeping with contemporary tastes. Little consideration was given to the medieval remains. The building facing the Rhine is only vaguely reminiscent of the former palace. The real Middle Ages are still preserved in the ruins of the keep as well as in parts of the mountain-side shield wall and the kennel.
In 1928 Katz Castle was auctioned off. In 1936 it fell to the Reich Labor Service. A training camp was set up at the castle.
After the Second World War, the Federal Republic of Germany became the owner of the castle as the legal successor to the German Empire. It initially served as a temporary school building for the Hofmann Institute.
The boarding school was opened in 1948 under the direction of the Altgelt family. Since the school in St. Goarshausen was partially destroyed due to the war, the high school was moved to specially built barracks on the castle grounds. After renovation in 1950–1951, the institute in the city became a secondary school again. The barracks were continued to be used by boarding school students for preparation.
Students from the Hofmann Institute boarding school were housed at the castle until 1966. In 1964 they moved into the newly built building of the now nationalized Wilhelm-Hofmann-Gymnasium in downtown St. Goarshausen.
Until the end of 1987, Katz Castle was a recreation center for the Federal Financial Administration's social welfare office. Due to a lack of a fire escape, the recreation center was closed and the castle was put up for sale. The Japanese management consultant Satoshi Kosugi acquired Burg Katz in 1989 for 4.3 million DM and originally wanted to have it converted into a hotel specifically for Japanese tourists.[1] The expansion did not take place.[2]
Today the castle is privately owned by Japan. A tour of the castle is not possible.