Father Reed takes us to the Papal Basilica of Saint Mary Major (Italian: Basilica Papale di Santa Maria Maggiore), an ancient Roman Catholic Marian basilica of Rome. It is one of the four major or four papal basilicas of Rome.
So cool! But also a large number of scholars actually date the Salus Populi Romani to the 6th century. There's definitely a range, but 13th century is pretty late based on the scholarship I've read - which could certainly be new in the last almost 7 years since this video was published!