Pope John Paul II's schedule for December 2004 is, for the most part, a mirror image of preceding years: Mass for university students on Dec. 14, the blessing of the statues of baby Jesus brought to St. Peter's Square by Roman children, an exchange of Christmas greetings with members of the Roman Curia, Midnight Mass on Dec. 24 in St. Peter's Basilica, the Urbi et Orbi blessing on Christmas Day in St. Peter's Square, and Vespers and the Te Deum of thanksgiving in the Vatican Basilica Dec. 31.

And, as he always does on Dec. 8, the Holy Father will mark the solemnity of the Immaculate Conception, first with Mass in St. Peter's Basilica and then with the traditional mid-afternoon visit to Rome's historic Piazza di Spagna to crown this statue of Our Lady in the heart of the Eternal City.

Dec. 8 will stand out for two reasons this year. Not only does 2004 mark the 27th time that John Paul has come to the piazza to pray and to pay homage to Our Lady, but it also celebrates the 150th anniversary of the proclamation of the dogma of the Immaculate Conception by Pope Pius IX.

The Pope in 1996 dedicated several of his weekly audience catecheses to this dogma. At the June 12 gathering, he told the faithful: “Down the centuries, the conviction that Mary was preserved from every stain of sin from her conception, so that she is to be called all holy, gradually gained ground in the liturgy and theology. At the start of the 19th century, this development led to a petition drive for a dogmatic definition of the privilege of the Immaculate Conception.

“Around the middle of the century,” he continued, “with the intention of accepting this request, Pope Pius IX after consulting the theologians, questioned the bishops about the opportuneness and the possibility of such a definition, convoking, as it were, a ‘council in writing.’ The result was significant: The vast majority of the 604 bishops gave a positive response to the question.”

Finally in 1854, with the Bull Ineffabilis Deus, Pius IX solemnly proclaimed the dogma of the Immaculate Conception: “We declare, pronounce and define that the doctrine which asserts that the Blessed Virgin Mary, from the first moment of her conception, by a singular grace and privilege of almighty God, and in view of the merits of Jesus Christ, Savior of the human race, was preserved free from every stain of original sin is a doctrine revealed by God and, for this reason, must be firmly and constantly believed by all the faithful.”

On Dec. 10, 1854, two days after proclaiming this dogma, Pius IX dedicated the newly restored patriarchal basilica of St. Paul Outside-the-Walls in the presence of all who had been there to hear the momentous proclamation: the complete College of Cardinals, the patriarch of Alexandria and 140 bishops. Their names, in fact, are inscribed on large memorial tables that appear below the mosaics in the basilica's semi-circular apse.

When the Pope arrives at Piazza di Spagna — named for the Palazzo di Spagna, a magnificent building on the square that has housed the Spanish embassy to the Holy See since 1647 — he will place flowers at the foot of the statue of Mary Immaculate. Early in the morning of Dec. 8, Roman firemen place a garland atop the statue of Mary, and by day's end, thousands of Romans will have followed in their footsteps, offering floral homages to Mary.

Single flowers, as well as bouquets, are placed on a table at the foot of the column bearing the statue where Conventual Franciscan Friars and Minim Friars arrange them in an orderly fashion, often creating elegant wreaths.

The ancient Roman column of cipolin marble came to light in 1777 in the monastery of Our Lady of the Conception in central Rome. Brought to Piazza di Spagna in 1856 by renowned architect Luigi Poletti to celebrate the proclamation of the dogma two years earlier, the column was topped by the bronze statue of Mary Immaculate by Giuseppe Obici and rests on an octagonal base decorated by statues of the prophets Moses, Isaiah, Ezekiel and David.

John Paul has celebrated the solemnity of the Immaculate Conception for 27 years — in summer-like warmth, under brilliant sunshine, in bone-chilling cold and under pouring rain. One of the most memorable visits was Dec. 8, 1993, the first time he had left Vatican City since dislocating his shoulder the previous Nov. 11.

Joan Lewis works for Vatican Information Service.