The cousins ​​did not want the meeting to attract too much attention for foreign policy reasons, and the small Russian border town of Fredrikshamn, or Hamina, was chosen as the location. The meeting of the rulers was organized in June 1783. For three days, the house was filled with the splendor of the courts in the form of receptions, receptions and evening parties. Between the two, the rulers negotiated in a small room, the so-called Catherine's chamber. Gustav's goal was to make Russia, led by Catherine, an ally in the war against Denmark. The empress, who acted diplomatically, did not agree to her cousin's plans and the negotiations ended in Hamina without success, but in good spirits.

From the 19th century, the building served as a private home. Over the years, there were several owners, and according to the custom of the time, the owners of the town house had tenants. In the 1940s and 1950s, there were also businesses in the building, such as a bakery cafe, a tailor's shop and the toy factory Haminan Laatulelu Oy.

The Town Museum has been operating in the building since 1957. At first, the museum premises were located in an 83-square-meter rented apartment, until the entire building became the property of the town and for the museum in 1980.

The Town Museum's exhibition Periods and Contemporaries comprehensively presents the stages of the city's development from the earliest settlement up to the 20th century. In the museum, you can see fascinating artefacts that bring to life written facts about, for example, shipping and the city's schools. The exhibition also presents famous people from Hamina, through whom the eras come alive. In the renovated Catherine chamber, you can try on royal outfits and set the mood with period music  while playing a game of chess.