On July 16, 2021, Pope Francis issued a bombshell decree restricting the pre-Vatican II Mass. It's called “Traditionis Custodes” or, in English, “Guardians of the tradition.” It overrides and reverses a 2007 decree from Pope Benedict that made generous accommodations for its use across the Catholic Church. Why did Francis reverse course? What does this mean for the Catholics who celebrate the pre-Vatican II Mass? And how will this decision affect the all-important unity of the Catholic Church? Colleen Dulle, host of America Media's "Inside the Vatican" podcast breaks it all down.