On the first Sunday of his papacy, Pope Leo XIV stood on the central Loggia of St. Peter's Basilica and did something that shocked some Catholics -- he chanted the Marian prayer Regina Caeli in Latin.

"Regina caeli, laetare, alleluia," he sang, leading to the crowd's response, "Quia quem meruisti portare, alleluia." In English, that would be: "Queen of Heaven, rejoice, alleluia. For He whom you did merit to bear, alleluia."

While many consider Latin chant controversial, the Pontifical Institute of Sacred Music immediately launched a project called "Let's Sing with the Pope." It offers "video tutorials on social media to help the People of God sing along with the Holy Father during the upcoming major liturgical celebrations," said Father Robert Mehlhart, on the institute's Instagram account.

The goal, he added, is to "make the rich heritage of Gregorian chant accessible to all."

So far, Pope Leo XIV has not addressed ongoing debates about restrictions on use of the Tridentine Mass, often called the "traditional Latin Mass." Bishops around the world have been pulled into these battles after the 2021 release of the Pope Francis apostolic letter "Traditionis Custodes (Guardians of Tradition)."

In 2023 remarks to Jesuits in Hungary, Pope Francis said stronger restrictions on use of the pre-Vatican II rite were necessary because of a state of "indietrismo" -- or "backwardness" -- caused by a "nostalgic disease" among many Catholics.

"After all the necessary consultations, I decided this because I saw that the good pastoral measures put in place by John Paul II and Benedict XVI were being used in an ideological way, to go backward," he added, in a transcript released by a Jesuit journal.

While use of the Latin Mass remains a flashpoint, a controversy in the rapidly growing Diocese of Charlotte, North Carolina, has raised questions about the status of other liturgical traditions and symbols.