The Gothic burgher's house at 15 Kopernika Street known as the Copernicus House was built in the 15th century. At the time of Copernicus's birth, it was property of his parents which is why it is considered as one of the likely birth sites of the renowned astronomer. In the 20th century, the house was restored to its original form and look from the 15th century, with richly ornamented fasade and crow-stepped gable, so typical for Torun townhouses at that time. In the Middle Ages, only three rooms in the building were inhabited, namely, the great entrance hall and rear chamber on the ground floor and one room overlooking the back yard on the first floor. The remaining floors served as storage space. Since 1973, together with the adjoining building, it has housed the Nicolaus Copernicus Museum.