Several explanations have been put forward for this unusually explicit allegory displayed in the most sacred place of Roman Catholic Christianity (the burial place of Saint Peter). 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. 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. A third tradition explains the allegory as Bernini's revenge against the pope's decision to disavow a child illegally born to his nephew Taddeo Barberini and the sister of one of Bernini's pupils.