Although not the oldest of the four Roman basilicas, Santa Maria Maggiore—where Pope Francis has requested to be buried—is the one that most evokes the atmosphere of the early centuries of Christianity. Despite the many precious renovations over the centuries, the basilica retains the layout from its foundation years; or rather, from its refoundation by Pope Sixtus III (432-440). The original church was built by Pope Liberius (352-366) following the miracle of Our Lady of the Snow: the legend states that on August 5, 368, an unusual snowfall indicated to the Pope and a pair of Roman patricians the location where they should build a Marian sanctuary. Since then, the miracle has been commemorated every year on the same date with a cascade of white petals falling from the coffered ceiling of the basilica.

Santa Maria Maggiore is also the church that houses the relics of the Holy Cradle, the five wooden boards of sycamore wood traditionally believed to be the first cradle in which the Infant Jesus was laid. These relics are displayed in a crystal reliquary shaped like a cradle, designed in 1802 by Giuseppe Valadier. The early Christian and medieval mosaics, shimmering in gold and various colors, are among the most precious treasures of Santa Maria Maggiore. Some of them have remained almost intact since the 5th century, especially those on the triumphal arch, which depict the infancy of Jesus.

The altar of the Pauline Chapel, where Bergoglio would gather in prayer, is illuminated by the icon of the Madonna Salus Populi Romani holding the Child. This image was especially dear to Pope Francis, also because it was venerated by the Jesuits (the order from which the Pope hails), who spread its devotion wherever they were present.