Designed by the Italian artist Gian Lorenzo Bernini, it was intended to mark, in a monumental way, the place of Saint Peter's tomb underneath.

The form of the structure is an updating in Baroque style of the traditional ciborium or architectural pavilion found over the altars of many important churches, and ceremonial canopies used to frame the numinous or mark a sacred spot.

[3] The old basilica had a screen in front of the altar, supported by 2nd century Solomonic columns that had been brought "from Greece" by Constantine I (and which are indeed of Greek marble).

These were by the Middle Ages believed to have come from the Temple of Jerusalem and had given the rare classical Solomonic form of helical column both its name and considerable prestige for the most sacred of sites.

[4] The bronze and gilded baldachin was the first of Bernini's works to combine sculpture and architecture and represents an important development in Baroque church interior design and furnishing.

Above this, four twice-life-size angels stand at the corners behind whom four large volutes rise up to a second smaller cornice which in turn supports the gilded cross on a sphere, a symbol of the world redeemed by Christianity.

[5] At this early stage in their careers, and before the bitter rivalry between the two ensued, Bernini worked in collaboration with Francesco Borromini who made drawings of the structure and who may also have contributed to its design.

Simultaneously, the hair becomes increasingly dishevelled; the eyes, which at first express a bearable degree of suffering, take on a haggard look; the mouth, closed at first, opens, then screams with piercing realism.

Some scholars favor a symbolic explanation, suggesting that Bernini intended to represent the labor of the papacy and of the earthly church through the allegory of a woman's pregnancy.

[7] A more popular tradition tells the story of the complicated pregnancy of a niece of Urban VIII's and of his vow to dedicate an altar in St. Peter's to a successful delivery.