Rome was bombed several times during 1943 and 1944, primarily by Allied and to a smaller degree by Axis aircraft, before the city was liberated by the Allies on June 4, 1944. Pope Pius XII was initially unsuccessful in attempting to have Rome declared an open city, through negotiations with U.S. President Franklin D. Roosevelt via Archbishop Francis Spellman. Rome was eventually declared an open city on August 14, 1943 by the defending Italian forces.

In war, an open city is a settlement which has announced it has abandoned all defensive efforts, generally in the event of the imminent capture of the city to avoid destruction. Once a city has declared itself open, the opposing military will be expected under international law to peacefully occupy the city rather than destroy it. According to the Protocol I of the Geneva Conventions, it is forbidden for the attacking party to "attack, by any means whatsoever, non-defended localities". The intent is to protect the city's civilians and cultural landmarks from a battle which may be futile.