Just like Urban VIII before him, Alexander VII commissioned Bernini to build his tomb. However, Alexander did not live to see the start of the tomb’s construction. It wasn’t until 1672, under Pope Clemens X, that work finally commenced, and the tomb was consecrated in 1678 under Innocentius XI. Bernini’s assistants did most of the actual work, although the design was of course Gian Lorenzo’s, and he closely monitored the execution.
Alexander VII’s tomb is located in the southwest corner of the basilica, above the Porta Santa Marta, behind which the sacristy used to be. A cloth of coloured marble is draped over the door. Alexander VII, is depicted in a kneeling position wearing a pluvial, his tiara lies inconspicuously beside him. Below the plinth one can see four life-size marble figures. In the foreground: Charity (holding a child) and to the right Truth with one of her feet on top of the earth (truth rules the entire world) and the sun’s rays in her hand. Behind these two figures are two more personifications: Justice and Prudence.
The pope initially wanted Modesty and Truth to meet and Justice and Peace to embrace each other. The Vatican eventually decided against the idea because of the late pope’s foreign policies; peace and modesty were not exactly the two qualities that this pope had excelled in. So the personifications of Modesty and Peace were replaced by Prudence and Charity.
The combination of Death and his hourglass directly above the middle of the doors refers to an old and long-lasting tradition in which these images represent the door that you eventually have to pass through and definitively close behind you. In the Chigi Chapel for example, you can read the motto ‘Mors ad Caelos’: Death opens the road to heaven. The doors under the niche suggest they lead to his grave.
Surrounded by these four virtues, Alexander VII is praying that his soul may triumph over death. Pope Alexander VII was obsessed with death. It is known that Alexander VII commissioned Bernini to build a casket for him only three days after he was elected pontiff. He placed this casket and marble skull (bottom) in his bedroom as a memento mori. Alexander VII also ate all his meals from dishes decorated with human skulls.
In 1656 Alexander met Gian Lorenzo to discuss the design of his tomb and the necessary marble was ordered straight away. After Alexander VII’s death Cardinal Flavio Chigi (L.F. Voet 17e eeuw) ensured that the tomb was completed as agreed. In 1672 Bernini received final payment for the tomb: 1000 scudi; the tomb was completed in 1678 (More information see Wikipedia).
Archaeological research has shown that the cathedra, or seat, dates from a later period.
“Around the inside of the dome is written, in letters 1.4 metres
TV ES PETRVS ET SVPER HANC PETRAM AEDIFICABO ECCLESIAM MEAM ET TIBI DABO CLAVES REGNI CAELORVM; you are Peter, and on this rock I will build my. and I will give you the keys of the kingdom of heavenVulgate Matthew 16:18 (Matthew 16:18)
Beneath the lantern is the inscription
S. PETRI GLORIAE SIXTVS PP. V. A. M. D. XC. PONTIF. V (To the glory of St Peter; Sixtus V, pope, in the year 1590, the fifth of his pontificate.” Source Wikipedia
You will get to see the wooden scale model of St Peter’s dome on the day of your visit to the Vatican Museum.