Four years after Pope Pius IX defined the Immaculate Conception as dogma in 1854, a French peasant girl named Bernadette Soubirous reported that a figure appearing to her at Lourdes identified herself, when pressed repeatedly for a name, by saying in the local dialect words rendered in French as I am the Immaculate Conception, a phrase Bernadette, who had not been taught the theological term, reportedly repeated to her parish priest without understanding what it meant, and Catholic sources treat her use of the exact newly defined phrase as significant corroborating evidence for the reported apparition's authenticity.
The Lourdes apparitions were investigated and eventually approved by the Catholic Church, and the shrine that grew up around the reported site has since become one of the most visited Catholic pilgrimage destinations in the world, drawing millions of visitors annually including many seeking healing at its waters, so that the 1854 dogma and the 1858 apparitions are now closely linked in popular Catholic memory and devotional practice even though the doctrine itself was formally settled independently of, and prior to, any apparition claim.
The United States bishops formally placed the country under the patronage of the Immaculate Conception in 1846, eight years before the doctrine was defined as dogma, a dedication now expressed physically in the Basilica of the National Shrine of the Immaculate Conception in Washington, D.C., one of the largest Catholic churches in North America and a major site of pilgrimage on the feast day itself.