The 19th century was marked by many events. On 10 January 1805 Pope Pius VII celebrated Mass in the church. In 1833, Frederic Ozanam, a parishioner of St. Stephen, founded with friends the Society of St. Vincent de Paul. On 3 January 1857 Bishop Marie-Dominique-Auguste Sibour, was assassinated with cries of "Down with the goddesses!" by the priest, Jean-Louis Verger, opposed to the dogma of the Immaculate Conception. A plaque at the entrance to the nave marks the grave of the prelate, who was to inaugurate the novena of St. Genevieve. The occultist Eliphas Levi was indirectly involved in this tragic event.