The Copenhagen Fire of 1728 is the largest fire in the history of Copenhagen . It began in the evening of October 20, 1728 and lasted until the morning of October 23. The fire destroyed about 28% of the city’s territory (measured by counting the number of destroyed buildings from the cadastre), made about 20% of the population homeless, and the reconstruction of the city after it continued until 1737. At least 47% of the part of the city that dates back to the Middle Ages was completely lost, and along with the fire of Copenhagen in 1795, this is the main reason that only a few traces of medieval Copenhagen can be found in Copenhagen today.
Although the number of dead and injured was relatively small compared to the extent of the fire, cultural losses were enormous. In addition to several private book collections, 35,000 texts, including a large number of unique works, were lost in the library at the University of Copenhagen and in the observatory at the top of the Round Tower , and instruments and recordings made by Tycho Brahe and Ole Roemer were also destroyed.