Le Pelerinage de Lourdes is the only encyclical of Pope Pius XII issued in French. It includes warnings against materialism on the centenary of the apparitions at Lourdes. It was given at Rome, from St. Peter's Basilica, on the feast of the Visitation of the Most Holy Virgin, July 2, 1957, the nineteenth year of his Pontificate. The encyclical represents so far the strongest pronouncement of the papal magisterium on Marian apparitions in the history of the Catholic Church.
The encyclical recalls pleasant memories of the pilgrimage to Lourdes which Pope Pius XII undertook as Papal delegate at the Eucharistic and Marian Celebrations in 1937. The Pope reminds the faithful of France, that every Christian land is a Marian land and that” there is not one nation redeemed in the blood of Christ which does not glory in proclaiming Mary its Mother and Patroness” He then recalls the history of Marian veneration, the history of Lourdes and the contributions of the Popes to her veneration in Lourdes.
Read more about Le Pelerinage De Lourdes: The Popes and Lourdes, The Challenge of Materialism