The book collection that once was in the Library Hall originally comprised about 10,000 volumes placed in bookcases lining the walls. One of the main attractions was a so-called book wheel, and a set of rules accurately stipulated how to behave.

Arriving in Copenhagen as a young man, Hans Christian Andersen visited the Round Tower as one of the first things and was allowed to use the books in the University Library – provided that he put the books properly away after use. Later he returned to the tower numerous times in his writings.

Danish prehistory was an impenetrable hodgepodge until it was divided into the Stone Age, the Bronze Age and the Iron Age in the 1820s. It happened in the Library Hall with entrance from the Round Tower and the division was of such a high calibre that it is still used internationally.

Christian IV was vividly concerned with the construction of the Round Tower. 177 years after his death, he returned to the tower in the shape of a seven-year-old boy on a woven tapestry. The tapestry formed part of the collection of antiquities and other things that started in the Library Hall and later became the National Museum of Denmark.

Huge canvases stretched on the floor were transformed into castles and fairy-tale gardens, when the Library Hall housed the studio of the famous theatre painter Carl Lund. But one of his employees was also interested in smaller pictures and took a selfie in colour as early as about 1910-12.