This location was once home to the Cadet School's ceremonial and administrative building, the Imperial Hall, which was completed in 1875. The building replaced the old administration building of the Cadet School. It housed a library, artillery museum, duty room, archive, and residential quarters for the commander of the cadet company, the class inspector, the adjutant, and the legal officer. The building featured a magnificent ceremonial hall.

Later, the building served as the headquarters and event space for the Reserve Officer School. It also housed the Hamina Military Home Association's soldier's home. During the Winter War, the building functioned as the headquarters for the Kotka sector and was damaged in bombings in March 1940. It was demolished after the Continuation War. The remaining bricks were used to build the new soldier's home of the Hamina Military Home Association in 1948 at Kadettikoulukatu 8. The current building on the site has housed various facilities over time, including a garrison cafeteria, apartments, a cinema, a lecture hall, a sauna, and a soldier's home.