Gregory the Great and the rearrangment of Saint Peter's Basilica.

When Gregory the Great (Gregory I –Gregory VII is also referred to as Gregory the Great just to make a historian’s life difficult) became pope in 590, he determined a renovation of the shrine over the tomb of the Apostle.  He raised the floor level of the Apse four and a half feet and built two flights of stairs to either side of and perpendicular to a level space just before the altar—much like the arrangement of the altar seen here at Santa Maria in Trastevere.  He located his Episcopal chair (since this church was (and is) not a cathedral the chair is technically not the pope’s cathedra) in the traditional spot, against the wall of the apse and directly behind the altar.  In addition to raising the level of the apse and placing his chair and benches for the clergy in what was the traditional Roman position lining the wall of the apse, Gregory wanted to have an altar for the celebration of the Eucharist.  You may remember that in Constantine’s basilica, the marble and porphyry monument encasing the trophy of Gaius —the brick plastered “red wall” that had been built over the tomb of Peter c. 150 AD —which took the traditional place of the altar as the focal point of the basilica.  In raising the level of the floor of the apse almost five feet, Constantine’s monument was all but buried; enough remained above the floor level to become the altar of the basilica.  Thus the altar contained within itself the ancient monument over Peter’s grave. 

A passage below the floor of the apse and following its curve gave access to a recessed chapel directly beneath Gregory’s main altar and in this chapel it was possible to have access to the tomb of the apostle by lowering pieces of cloth to the tomb below and then withdrawing the cloth to keep as a relic.  Although Constantine’s basilica itself is gone—and Gregory’s apse with it—one can still walk this curved passageway today in the “grottoes” beneath the current Saint Peter’s and there enter the chapel, now called the Clementine Chapel after Pope Clement VIII who refurbished it at the very end of the sixteenth century.  Behind the altar there is a grille and through the grille one can see the marble and porphyry monument that Constantine had erected over the tomb of the apostle which served as the altar in Gregory’s day and which lies directly beneath the current papal altar of the new basilica; the altar was consecrated by Clement VIII June 5, 1594.  Until about ten years ago this passage was regularly open to pilgrims, but the series of chapels that line the ancient apse are now usually open only early in the morning when they are used for the dozens of masses visiting priests and Vatican regulars use to say mass.  The chapels have proved too difficult to protect in this age subject to terrorist threats and so they are sealed during the day.     

Gregory was not the only pope to make changes in the basilica.  Over the centuries there was a constant need for repair and addition to the basilica as well as for decoration.  In fact, popes often paid more attention to the decoration than to the maintenance of the fabric which is one of the reasons the basilica eventually would have to come down and be replaced in the sixteenth century.  The rich décor along with immense quantities of gold and silver votive offerings adorned with gems sometimes serve to tempt foes to sack the basilica.  Honorius I (pope 625-638) took the tiles from the Basilica of Maxentius (a secular building, not a worship site) in the Forum to re-roof St. Peters.  In 846 Saracen pirates sacked the basilica and took many valuable items with them.  Gregory IV (827-844) rebuilt the Atrium—the spacious colonnaded courtyard in front of the basilica proper.   In the middle of the eleventh century the building, at that point seven centuries old, was in danger of collapsing and a succession of popes, though largely unsuccessful in raising funds to carry out the work as properly as it should have been done, did what they could to strengthen the structure of the building.  Remember, however, that this was not the principal church of Rome at the time.  The Pope’s Cathedral was (and still is) the Basilica of Saint John Lateran and it was at the Lateran—not the Vatican—where the pope resided and normally carried out ceremonies. 

One ceremony that was carried out in Constantine’s Basilica of Saint Peter was the coronation of Charlemagne on Christmas day in the year 800.  Charlemagne’s family—the Pepinid dynasty—were the traditional protectors of the papacy. In fact they owed their legitimacy to the papacy as they had been “mayors of the palace” to the legitimate kings of the Franks—the Merovingian dynasty—and when the Merovingians proved too weak to protect France, much less the papacy, the Pepinids sought and received the papal blessing to overthrow the Merovingians and replace them.  As the Merovingians had been descended from Clovis—for whose baptismal and coronation anointings the Holy Spirit herself had supposedly sent from heaven a holy oil it would take at least a papal benediction to authorize a new dynasty on the throne.  When Pope Leo III had been threatened with being deposed by his clergy for various immoralities, Charlemagne came to Rome to adjucate the case himself.   When Leo proved his innocence to Charlemange’s satisfaction he then crowned Charlemagne emperor of a revived Roman Empire.  The idea did not catch on at once; the empire would more or less fall apart when upon his death Charlemagne divided his realms among his three sons. However his great great great grandson, Otto of Bavaria would revive it—but that leads us in another direction.  When receiving his crown, Charlemagne knelt on a circle of porphyry about 5 feet in diameter that was set before the altar of the basilica.  Porphyry was (and is) an exceptionally precious stone and its use was reserved for the emperor.  During the central Middle Ages it became a tradition that the emperors would kneel on this stone when being crowned in Rome.  That same stone can be found in the floor of today's basilica just inside the central doors leading from the modern atriun into the basilica proper.