The Archdiocese of Philadelphia will observe the 100th anniversary of the apparition of the Blessed Virgin Mary to three shepherd children in Fatima, Portugal with a Mass on Oct. 15 at 11 a.m. celebrated by Archbishop Charles J. Chaput at the Cathedral Basilica of SS. Peter and Paul.

At that time the archbishop will officially consecrate the entire archdiocese to Our Lady of Fatima.

In a sense it will be a re-consecration, because the archdiocese was consecrated to the Immaculate Heart of Mary by Archbishop John F. O’Hara at the Shrine of Our Lady in Fatima in Portugal in 1952.

The consecration to Our Lady is the Philadelphia response to a decision by the Catholic Bishops of Pennsylvania to consecrate the entire state to the Immaculate Heart of Mary, according to Meghan Cokeley, director of the archdiocesan Office for the New Evangelization.

“The Pennsylvania consecration is set for Sept. 27 in Harrisburg, and the various dioceses are having their own ceremony in their own community,” Cokeley said.

Other local devotions in conjunction with the centennial have been held on the 13th of each month since May in parishes including St. Ignatius, Yardley; St. Paul, Philadelphia; the Cathedral Basilica, Philadelphia; St. Mary, Schwenksville; Sacred Heart, Bridgeport and the Shrine of Our Lady of Czestochowa, Doylestown.

The timing of the consecrations is significant because it approximates the dates of the six apparitions to the children beginning May 13, 1917 and ending Oct. 13, 1917.

The three children were Lucia Santos, 10 and her cousins Francisco and Marta Santo, age 9 and 7. Francisco and Marta who died shortly after during the influenza pandemic in 1919-20, and were canonized by Pope Francis at Fatima on May 13 of this year. Lucia became a nun and died in 2005 at age 97. Her cause for canonization is currently under consideration.

This centennial year there have been a number of devotions in various parishes to Our Lady of Fatima centered around the 13th of the month between May and October, mostly sponsored by the World Apostolate of Fatima, formerly known as the Blue Army.

One devotion Cokeley recommends is the 33-day preparation generally used for all Marian celebrations as formulated by St. Louis de Montfort in the early 18th century. “Preparation for Total Consecration” by St. Louis de Montfort can be found on Amazon.com.

A modern version, which is also available on Amazon, is “33 Days to Morning Glory.” It was compiled by Father Michael Gaitley and based on the writings of four saints with a special devotion to Mary: St. Louis de Montfort, St. John Paul II, St. Teresa of Calcutta and St. Maximilian Kolbe.

Both versions of the consecration and additional resources are available on the website through MyConsecration.org.

“It captures what four saints say in their reflections on Our Lady and how she brings us into intimacy with Jesus,” Cokeley said.