Things at the Vatican grind to a near standstill in August as Vatican offices close and people go on vacation. But for those who stay in Rome, there's an annual reminder of the Blessed Mother's care for the Church.

The feast of Our Lady of the Snows was commemorated Aug. 5 with a solemn high Mass at the Basilica of St. Mary Major. During the Mass, thousands of flower petals were released from the ceiling and outside from the rooftop, showering the faithful who gathered to commemorate the event.

This unusual liturgical flourish harks back to the year 358, when a Roman patrician named John and his wife, unable to have children, were praying to the Virgin Mary, asking her to give them a sign as to whom they should leave their enormous patrimony. On the night of Aug. 4-5, one of the hottest of the year, Mary appeared to the couple in a dream and requested that they build a church in her honor where snow would fall that night.

Friends of the Holy Father, John and his wife went to tell Pope Liberius of their dream — and discovered he had the same one. The next morning, Aug. 5, the highest of Rome's seven fabled hills, the Esquiline, was covered in snow, as witnessed by John, his wife, the Pope and his entourage, and a throng of Romans. Pope Liberius took a stick and traced the sign of the future basilica in the snow, a basilica that would be forever known as Our Lady of the Snows.

Since it is considered the greatest Marian church, the basilica is also called St. Mary Major. It is also known as the Liberian Basilica (for Pope Liberius).

The first church was built on the site of an ancient market and close to the Temple of Juno Lucina. Throughout the centuries, it underwent changes, modifications and additions.

Much of the basilica we see today is courtesy of Pope Sixtus III (432-440). Sixtus became Pope one year after the Ecumenical Council of Ephesus (in modern-day Turkey), which recognized Mary as “Theotokos,” the Mother of God. He wished to honor this, the most noble of all of the Blessed Virgin's titles, and thus it was he who gave the basilica much of its current structure and form as well as the magnificent mosaics on the triumphal “Ephesus” arch, which is above and behind the main altar and which depicts scenes from the New Testament.

One of the five patriarchal basilicas of Rome, Our Lady of the Snows is the third-most-visited monument in Rome after St. Peter's and the Colosseum. It is famous for housing the image of Our Lady known as “Salus Populi Romani,” which is revered by Romans and which tradition says was painted by St. Luke.

It is also home to the relic of the crib of the Baby Jesus. A horseshoe-shaped double staircase descends from the main altar and leads to a small chapel with the relics of the manger crib in which the Christ child was laid the night he was born. The crystal, silver and gold reliquary containing the wood remnants was executed by Valadier in 1802 on a commission by Pope Pius VII (1800-23) who intended it to be in place for the Holy Year 1825. It replaces two previous reliquaries, the first of which was stolen in 1527, during the Sack of Rome, and the second in 1797 by Napoleon's troops.

Pilgrims flock to Our Lady of the Snows to see its stunning ceiling, commissioned by Pope Alexander VI (1492-1503) for the Holy Year 1500. It consists of 105 wood-carved panels, each a meter square, which were placed over the former trussed ceiling and then gilded with some of the gold brought from the newly discovered Americas by Columbus and given to King Ferdinand and Queen Isabella of Spain. The Spanish Royals donated this Peruvian gold to fellow Spaniard Pope Alexander VI.

As it has almost every year since 358, St. Mary Major Basilica celebrated its feast day in early August. Three days of festive preparation, encounters and religious events preceded a Pontifical Mass the evening of Aug. 5.

As always, flower petals fell from the ceiling, symbolizing that miraculous snowfall in August.

Joan Lewis works for Vatican Information Service.