"This feast commemorates the miracle of the snowfall that occurred during the night of August 4-5 in the year 358 on the site where the basilica now stands. According to tradition, the Virgin Mary appeared in a dream to two faithful Roman Christians, the patrician John and his wife, as well as to Pope Liberius (352-366), asking that a church be built in her honor on the site where snow would fall on the night of August 4-5. Pope Liberius traced the outlines of the church in the snow and the first basilica was built on that site. It was completed about a century later by Pope Sixtus III (432-440), after the Council of Ephesus in 431 during which Mary was declared to be the Mother of God. In Rome the Basilica of St. Mary Major holds its traditional triduum from August 1 to 3 and two days of celebration on August 4 and 5. During the pontifical Mass and the second vespers, the traditional shower of flower petals will descend from the ceiling of the basilica to commemorate the August snowfall in 358."