The article is based on the sources kept at the Archives of the University of Wroclaw. The main aim was to present the activity of Professor Modelski, a historian-medievalist, a person of merit for the scientific environment of Wroclaw, who originally, before the War, worked at the University of Jan Kazimierz in Lwów. The University of Wroclaw and Technical University of Wroclaw were created on August, 24th, 1945. Soon, on January, 15th, 1946 Modelski became a professor at the Department of Medieval History at the Faculty of Humanities. The professor was presented mainly as an organizer and the first director, from 1946 up till 1962, of the Archives of the University. He did a lot to safe, bring together and set in order of, invaluable for researchers, the archives of the German institutions - Universitat Breslau (from 1911 - Schlesische Friedrich Wilhelms-Universitat) and Technische Hochschule, existing from 1910.