The National Museum in Krakow at the time when Poland regained independence had not yet been an object of academic studies. The author focuses here on the most important events and developments in the institution during that period, and on the professional and moral stance of its director Feliks Kopera. The director’s key mission was the complete protection of the collections and the institution itself. Kopera had no hesitation in criticising negligence and impropriety, which was a brave but often unpopular approach. His ideas were seldom in line with those of the decision makers in Warsaw. A fragment of the museum’s history discussed here reveals one of its most difficult periods.