From the beginning of the 16th century, the University’s main building had been used for storing memorabilia, and in the 18th century Collegium Maius came to be called a museum. After World War II, by the decision of the Jagiellonian University Senate, the Jagiellonian University Museum was established with its seat in Collegium Maius. This event officially sanctioned a centuries-old tradition of collecting University memorabilia. In the 1960s, after 15 years of renovation, the rooms of the newly established Museum were filled with treasures: works of art saved after World War II, valuable duplicates from the Jagiellonian Library, relics from the Jagiellonian University Astronomical Observatory, from academic chairs and departments. In the vestibule, visitors’ attention is drawn to the musical clock, the fourth mechanical clock in the history of the building. The first one was probably built at the end of the 15th century, while the present one dates back to the year 2000. The computer system launches a puppets’ procession accompanied by the melody of the academic song Gaudeamus igitur and a motif from a 16th-century tablature by Jan of Lublin. There are six figures moving in the procession: a beadle, Queen Jadwiga, King Władysław II Jagiełło, St. John Cantius, the educational reformer Hugo Kołłątaj and the 15th-century President (Rector) of the University, Stanisław of Skalbmierz.