Pope Francis will consecrate Russia and Ukraine to the Immaculate Heart of Mary later this month, the Vatican announced on Tuesday. 

What does that mean exactly, and why is this significant? Here’s what you need to know:

“Consecration” Means Being Set Aside for a Holy Purpose. 

You may or may not have heard of the concept of consecration before. A person— or nation— that is consecrated is set aside for a holy purpose. The word “entrustment” is often used synonymously with the word consecration. 

The Vatican's Congregation for Divine Worship defines consecration to Mary as an overt recognition of the “singular role of Mary in the Mystery of Christ and of the Church, of the universal and exemplary importance of her witness to the Gospel, of trust in her intercession, and of the efficacy of her patronage.”

Pope St. John Paul II — who consecrated the entire Church and world to Mary three times during his pontificate — taught that by consecrating oneself to Mary, we accept her help in offering ourselves fully to Christ.

Mary Specifically Asked that Russia be Consecrated to Her Immaculate Heart. 

The 1917 apparitions at Fatima are some of the world’s most famous Marian apparitions. 

In the course of her appearances, Mary revealed three secrets, the second of which was a statement that World War I would end, as well as a prediction of another war that would start during the reign of Pius XI if people continued to offend God, and Russia was not consecrated to Mary’s Immaculate Heart.

Sister Lucia, one of the three Fatima visionaries, said that Mary told her: “If my requests are heeded, Russia will be converted, and there will be peace; if not, she will spread her errors throughout the world, causing wars and persecutions of the Church. The good will be martyred; the Holy Father will have much to suffer; various nations will be annihilated.”

“In the end, my Immaculate Heart will triumph. The Holy Father will consecrate Russia to me, and she shall be converted, and a period of peace will be granted to the world."

In the years following the revelation of the secret, there was some controversy as to whether various consecrations of Russia performed by subsequent popes fulfilled the requirements set forth by Mary. 

But in a letter written in 1989, Sister Lucia confirmed that Pope St. John Paul II satisfied Mary’s request for Russia's consecration in 1984. At the time, Ukraine was still a part of the Soviet Union. 

Other authorities, including the Congregation for the Doctrine of the Faith, also have affirmed the consecration was completed to Sister Lucia's satisfaction.

Ukraine’s Latin Rite Catholic Bishops Requested that Pope Francis Do the Consecration, Amid the Invasion of Their Country. 

Ukraine’s Latin Rite Catholic bishops— meaning the bishops who lead the country’s Roman Catholics— sent a letter to Pope Francis on March 2 asking him to “publicly perform the act of consecration to the Immaculate Heart of Mary of Ukraine and Russia, as requested by the Blessed Virgin in Fatima.”

Russia Has Been Consecrated Before. So Has the Whole World, Actually. 

In the past, several popes have consecrated the entire Church and world to Mary.

Pope Pius XII consecrated the entire world to the Immaculate Heart of Mary on Oct. 31, 1942, and Pope St. John Paul II renewed that consecration on May 13, 1982, again on March 25, 1984, and once more on Oct. 8, 2000.

Pope Francis during Oct. 2013 renewed the consecration of the world to the Immaculate Heart of Mary, and dedicated his pontificate to Our Lady of Fatima.