Commissioned by Pope Pius IX (1846-78), Roman architect Virginio Vespignani built the Confessio (1861-64) in front of the Papal Altar. Vespignani used some 70 different types of marble, mostly from extractions that occurred concurrently in Rome and Ostia.

The Confessio recalls the importance of Saint Mary Major as the Bethlehem of the West and as Rome’s Basilica of the Nativity. Starting from the Pontificate of Theodore (642-649), native from Jerusalem, it was also known as Sancta Maria “ad Praesepem”. The Title refers to the five pieces of sycamore wood (ficus sycomorus), that were part of the manger upon which Baby Jesus was laid. Recent scientific studies date the wooden pieces, which are kept in a crib-shaped crystal reliquary designed by Giuseppe Valadier (1802), to the time of Jesus’ birth.