The Osteiner Hof in Mainz is an important baroque aristocratic palace built between 1747 and 1752. It was commissioned by Elector Johann Friedrich Karl von Ostein for his brother Franz Wolfgang Damian von Ostein. The architect Johann Valentin Thomann designed the building, which is located on Schillerplatz, which was then known as “Thiermarkt”.
During its history, the Osteiner Hof served various purposes. In the 19th century, it was the seat of the fortress commander. During the First World War, General Hugo von Kathen announced the start of the war here. During the Nazi era, the building was briefly handed over to the NSDAP in 1933 and later housed the Wehrmacht's city command.
After severe damage in the Second World War, the Osteiner Hof was rebuilt by the French occupying forces in 1947/48. Until 2014, it served as the Bundeswehr's base command. Today the building is used as a residential and commercial quarter and offers modern living space as well as room for young artists.
The Osteiner Hof is also a central location for the Mainz carnival: every year on November 11th the carnival season is opened from the balcony of the building.