The façade of the church of Santi Apostoli is crowned with thirteen statues of Christ and his Apostles. Each of the pedestals on which the statues stand is inscribed with a single letter. Christ, for example, stands above the letter O. But what do the thirteen letters (F. L. D. L. C. S. O. T. C. E. C. V. B.) actually stand for?
The façade was originally built at the end of the 15th century by Baccio Pontelli (1450-92). Pontelli's design was changed in the 17th century when Carlo Rainaldi (1611-91) walled up the arches on the upper level, altered the windows to the Baroque style and added the statues of Christ and the twelve Apostles.
The work was paid for by Cardinal Lorenzo Brancati, who was the chief librarian at the Vatican. The cardinal wanted his patronage to be recognised, but he knew a full-blown inscription would not be acceptable to the church. And so he came up with something more subtle.
The thirteen letters stand for:
Frater Laurentius De Laureolo Consultor Sancti Officii Theologus Cardinalis Episcopus Custos Vaticanae Bibliothecae (Brother Lorenzo de Laureolo, Advisor, Theologian of the Holy Office, Cardinal, Bishop, Guardian of the Vatican library).