Pope Francis will consecrate Russia and Ukraine to the Immaculate Heart of Mary, during a Penance service in St. Peter’s basilica on March 25: the feast of the Annunciation.

The consecration, announced by the Vatican on March 15, is a direct response to a request from the Latin-rite bishops of Ukraine, who had asked the Pontiff to make the consecration “as requested by the Blessed Virgin at Fatima.” The Ukrainian bishops asked for prayers for the conversion of Russia to be said at Marian shrines worldwide.

Sister Lucia, one of the Fatima seers, reported that the Virgin Mary had asked for the consecration of Russia to her Immaculate Heart. Sister Lucia testified in 1989 that Pope John Paul II had fulfilled the terms of the Virgin’s request.

The Vatican announced that while the Pope performs the consecration in Rome, Cardinal Konrad Krajewski— the papal almoner, who recently returned from a visit to Ukraine— will make the same consecration in a ceremony at Fatima.