In 1777 a veined-cipolin column was found during works for enlargement of the convent of the Benedectine nuns of S. Maria in Campo Marzio. It was almost 12 meters high and had a diameter of almost 1 meter and a half. Due to its incompleteness it was clear that the column had never been used and maybe lay in a marble workshop. Pope Pius VI did not like its roughness and it lay idle for almost 80 years, when Pope Pius IX decided to make of it the base of a Christian monument.
In 1854 Pope Pius IX pronounced the creed of the Immaculate Conception and had a statue of the Madonna placed on the top of the column. The monument was placed near the college of Propaganda Fide, where the missionaries were trained. Its base is decorated with statues of the Prophets: Moses, Isaiah, Ezekiel and David. Among them, four bas-reliefs recall the Annunciation, S. Joseph’s dream, the coronation of the Virgin and the pronunciation of the dogma.
On top, the emblems of the evangelists and the statue of the Madonna were casted in bronze in the Vatican foundries. The column was erected in 1857 by 200 firemen in a short time. Since then, the Immaculate is celebrated on 8 December, when a fireman climbs up to the statue and places a garland of flowers around the Virgin.