In World War II, the hall housing the armoury was damaged by aerial bombardment on 7 April 1942. The collections were subsequently transferred to the basement of the Grandmaster's Palace or to Girgenti Palace for safekeeping. The hall was repaired after the war, and the armoury reopened in 1948. In 1969, UNESCO sent Polish experts Aleksander Czerwiński and Zdzisław Żygulski to make an inventory of the armoury, and they called it one of "the most valuable historic monuments of European culture" in their report.