The need to eliminate Les Innocents gained urgency from May 31, 1780, when a basement wall in a property adjoining the cemetery collapsed under the weight of the mass grave behind it. The cemetery was closed to the public and all intra muros (Latin: “within the [city] walls”) burials were forbidden after 1780. The problem of what to do with the remains crowding intra muros cemeteries was still unresolved.[citation needed]
Mine consolidations were still occurring and the underground around the site of the 1777 collapse that had initiated the project had already become a series of stone and masonry inspection passageways that reinforced the streets above. The mine renovation and cemetery closures were both issues within the jurisdiction of the Police Prefect Police Lieutenant-General Alexandre Lenoir, who had been directly involved in the creation of a mine inspection service. Lenoir endorsed the idea of moving Parisian dead to the subterranean passageways that were renovated during 1782.[citation needed] After deciding to further renovate the “Tombe-Issoire” passageways for their future role as an underground sepulchre, the idea became law in late 1785.[citation needed]
A well within a walled property above one of the principal subterranean passageways was dug to receive Les Innocents’ unearthed remains, and the property itself was transformed into a sort of museum for all the headstones, sculptures and other artifacts recuperated from the former cemetery. Beginning from an opening ceremony on 7 April the same year, the route between Les Innocents and the “clos de la Tombe-Issoire” became a nightly procession of black cloth-covered wagons carrying the millions of Parisian dead. It would take two years to empty the majority of Paris’s cemeteries.
Cemeteries whose remains were moved to the Catacombs include Saints-Innocents (the largest by far with about 2 million buried over 600 years of operation), Saint-Étienne-des-Grès[better source needed] (one of the oldest), Madeleine Cemetery, Errancis Cemetery (used for the victims of the French Revolution), and Notre-Dame-des-Blancs-Manteaux. By this way the skeletal remains of several leaders of the French Revolution including Maximilien Robespierre and Georges Danton were transferred to the Catacombs.
