A well-promising development of the University was interrupted by the outbreak of the Second World War in the year of 1939. The Germans occupied the building of KUL, stealing and destroying the university’s property, burning furniture, scientific equipment, books and exhibits of the University Museum. They also applied home arrest for Rev. Szymański, Rector, and imprisoned professors, many of whom they executed. Repressions did not spare the students. Mass arrests, hearings, deportation to forced labor in Germany and to concentration camps became a daily drama of Nazi occupation. Names of the students and employees of KUL can also be found on the lists of victims shot by Russians in Katyn. Despite all these repressions throughout the years of war, the University conducted clandestine teaching in Lublin and other cities of Poland.