San Lorenzo fuori le mura in the context of Papal minor basilica

Rome, along with Vatican City, 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 (later Cardinal) Francis Spellman. Rome was eventually declared an open city on August 14, 1943 (a day after the last Allied bombing raid) by the defending Italian forces.

The first bombing raid was on July 19, 1943, when 690 aircraft of the United States Army Air Forces (USAAF) flew over Rome and dropped 9,125 bombs on the city. Though the raid targeted the freight yard and steel factory in the San Lorenzo district of Rome, Allied bombs also struck the district's apartment blocks, damaging the Papal Basilica and killing 1,500 people. Pius XII, who had previously requested Roosevelt not to bomb Rome due to "its value to the whole of humanity", paid a visit to the affected regions of the district; photographs of his visit later became a symbol of anti-war sentiments in Italy. The Allied bombing raids continued throughout 1943 and extended into 1944. In the United States, while the majority of the American media supported the bombing raids, many Catholic newspapers condemned them.

The Catacomb of San Lorenzo or Catacomb of Cyriaca is a five-level catacomb on via Tiburtina under the church of San Lorenzo fuori le mura in the modern Tiburtino quarter.

Its most common dedication in the ancient sources is to Saint Laurence, buried in it - the mid 4th century Depositio martyrum states he was buried on 10 August "in Tiburtina" but does not give a name for the cemetery, showing that by the time of writing it was already named after Laurence. Other sources name it after Ciriaca, owner of the land on which it was dug - the Liber Pontificalis and a 6th century martyrdom account of Saint Laurence states he was buried "on the via Tiburtina in land belonging to the widow Cyriaca in the ager Veranus", whilst 8th century sources even call her "beatus".