St. Peter's Basilica - A Virtual Tour
Text from the CD-ROM ©1999 Our Sunday Visitor
(all rights reserved)

The Square

Vatican City

Colonnade Saints
Floorplan #2







The Dome
The Square
The Obelisk
The Fountains
Bernini's Project
Constantine's Church
St. Peter's Grave
The Old Basilica
Holy Roman Emperors
The Two Churches
Julius II
Michelangelo's Design
Building the Basilica
Toward Completion
The Bell Towers
The Atrium
Filarete Door
Holy Door
Entering the Basilica
Interior Decoration
Founding Saints

Dome Decoration


The Crossing Statues
The Loggias

Statue of St. Peter
Pieta Chapel
Right Aisle
Blessed Sacrament Chapel
Monument to Gregory XIII
Gregorian Chapel
Right Transept
Michelangelo Ambulatory
Main Tribune
Monument to Urban VIII
Left Ambulatory
Monument to Alexander VII
Left Transept
Clementine Chapel
Choir Chapel
Innocent VIII Monument
Presentation Chapel
Stuart Monument
Baptistery Chapel


The Dome

The dome of St. Peter's Basilica has been the major landmark in the city of Rome up to the end of the 19th century. A mass emerging from the panorama on the horizon, just as it must have appeared to pilgrims traveling toward it. It was an unforgettable, strong image immediately rising up as a unifying symbol to broadcast the message of the Church and Christianity.

In effect, this was the intention of the Papacy, and this is how Michelangelo interpreted it, providing a landmark and a guide to the eyes and souls of pilgrims, coming from the Jubilee in 1600. The Cupola, or "cupolone" (big dome), as it is commonly called by the people of Rome, is the most significant part of the Basilica, and it is the most characteristic sight in the city, having by now taken the place of the Coliseum as the most significant symbol of the Eternal City, now known more widely as a center of Christianity than as the Urbe of the ancient Roman civilization.

This artistic masterpiece of all times, which still dominates the panorama in Rome from wherever one looks, even from the sky, was built from the design by Michelangelo, who supervised the work on it until the completion of the tambour. On his death, in 1564, Giacomo Della Porta assisted by Domenico Fontana took over the project and almost finished construction in less than two years, from July 15, 1588, to May 21, 1590. In this period too, construction of the lantern, requiring seven months, was also completed.

Today, visitors arriving at the Basilica on foot, have a clear view of the front of the dome from the Via della Conciliazione. After the end of World War II, the road was opened up by the architect Marcello Piacentini who, with a decision open to criticism, demolished a group of houses closing the opening to St. Peter's Square, known as the "Spina di Borgo."

This has opened up the view of the face of the dome from a distance but, at the same time, it diminishes the effect of warmth and universal welcome to visitors and pilgrims coming on foot to the Basilica, both spectacularly and harmoniously devised by the genius of Bernini.

The effect had been achieved by the building of two magnificent semicircles of quadrupled rows of Doric columns connected by an upper entablature crowned by a series of 140 Statues of Saints and the coat of arms of Pope Alexander VII. It was a masterpiece in layout that, between 1656 and 1667, Bernini ingeniously completed the space in front of the facade, which had itself been terminated by Carlo Maderno between 1607 and 1614, save later and additional alterations to the interior and exterior of the laborious and often tormented construction of St. Peter's Basilica.

The Square

Before mentioning, however, the methods used and the time taken to construct this building, which replaced an older early Christian Basilica dating from the time of Constantine, and before beginning a guided tour of the temple of Christianity, it is worth stopping to look in more detail at the square, for which Bernini designed, as his drawings show, an arrangement different and contrasting to the present one, with a third section of colonnade in place of the so-called "Spina di Borgo."

The entrance to the square, through two lateral passages at the sides of this colonnade, would have produced a greater stage-setting effect, but at the same time, would have exalted the feeling of awe and meditation in the believers, who would have felt themselves to be welcomed into the arms of the Christian Church, as ideally visualized in Bernini's famous drawing where the church is the head and the colonnades are the open arms of a human figure.

This is an effect which is still possible simply by superimposing, at the entrance to the square, a hypothetical colonnade to produce the spectacular result which Bernini pursued, obscuring the view of the façade from the distance, but not of the dome rising above it.

In reality, the solution chosen by this absolute protagonist of Roman art in the 1600s, whose career was so closely linked to the commissions he was given in the Basilica, was ingenious but at the same time lucidly rational.

In his design for the very vast surface of the square, which at that time may have appeared to be overlarge, Bernini abandoned Bramante's project envisaging four straight arcades arranged to form a square, adopting an oval shape which, however, was not favorably viewed by Alexander VII.

The Pope, in fact, judged it to be "not particularly in harmony with the design of the façade" and additionally, rather costly already in the planning phase.

Yet with this solution, placing two arcs of a circle beside a rectangular space, Bernini achieved the striking and amplifying effects of an elliptic plan; that is the impression of a space larger than it actually is by dynamic articulation of the square, stretched by its two lateral containing structures.

At the same time, he knew how to avoid the risks which this elliptic solution might present from the perspective point of view, by aligning two centers (not focal points) on a very long axis passing through the central obelisk. In this way, he was able to maintain the columns equidistant from one another and then, by gradually increasing the diameter of the columns, so that those in the internal row are the most slender and the external ones are the thickest, he was also able to maintain an equal distance between the intercolumniations.

Hence, if we stand on one of the two disks at the side of the obelisk, the columns appear as one row and not four in all parts of the semicircles. This is both a technical and an artistic device, which permits anyone moving around the square to enjoy the effects of a lively theatrical spectacle, but also of control of the immense space; it is a grandiose solution but at the same time is on a human scale.

With this creation, balanced between his effervescent imagination and his never denied classical vein, which here is inspired by the simplest of the ancient Greek styles, the Doric order, Bernini was able to offer Christianity its ideal epicenter.

In modern times, the function of this epicenter has been confirmed even without any special events, by the Pope's Sunday message, instituted by Pius XII and continued by his successors, with a simple but vibrantly human and spiritual contact between the Shepherd of Men and the always numerous crowd gathered in the square.

Lastly, it must be remembered that Bernini, in the final layout of the square, had to respect various differing and contrasting requirements. First and foremost was the view of the dome the soaring vertical lines of which, with the building of the façade, had been considerably diminished, at least for anyone standing in the space directly in front of the Basilica, still far from achieving the harmonious layout it was to have.

The Obelisk

Its center had, in any case, already been chosen for some time, with the erection there of the obelisk, the ancient center of Nero's Circus, which was still standing on its original site close to the present Sacristy when Pope Sixtus V, that great erector of obelisks, decided to move it in front of the existing façade of the Old Basilica, behind which Michelangelo's dome was being built.

In order to understand, at least in general, the complex and intricate succession of work on the Square in front of the Basilica during the 16th century, it is helpful to look at a print dated 1577 by Duperac-Lafréry showing, beside the Vatican buildings, a birds-eye view of the irregular surface of the square itself, with only the fountain on the right already built.

Another interesting illustration of the obelisk is contained in the fresco "Coronation of Pope Sixtus V" in 1585, in the Sistine Hall of the Vatican Library. In it, as in other engravings, the obelisk is still standing to the left of the Basilica.

An anonymous painting in the Museum of Rome, illustrating the Corpus Christi Procession, shows St. Peter's Square with the obelisk already in place, before the colonnades were built. This monolithic obelisk in red granite, 25 meters high and weighing approximately 1 million pounds, had been taken from the city of Alexandria by Caligula (37-41 A.D.) to be placed on the spine of the circus later to be known as Nero's, situated to the left of the Old Basilica.

Given the difficulty of moving it, several projects were considered until Sixtus V entrusted the job to his favorite architect, Domenico Fontana, who presented a wooden model, containing a lead grid, a replica of the obelisk, which could be easily lowered and raised. His project met with the Pope's approval and on April 30, 1586, transport was begun, after a solid foundation had been built to support the obelisk in the center of the square but not on the median axis of the façade of the Basilica.

The operation, which is illustrated by several engravings, was carried out using hemp ropes and iron bars weighing 40,000 pounds, plus 900 men and 72 horses, and was completed on Sept. 10 of the same year.

There is no truth in the story of "water on the ropes" which is supposed to have occurred during the raising of the obelisk, the work on which was, however, suspended during the summer. On the top, in place of the golden urn, said to contain the ashes of Caesar, was placed a bronze emblem of Pope Sixtus containing a relic of the cross. At the base are four bronze lions supported by a high pedestal.

The Fountains

The engraving by Duperac-Lafréry clearly shows that for some time in the square there had already been the fountain with three bowls one above the other, which Pope Innocent VIII had had built in 1490 and which was later to be renovated by Maderno in 1613 according to the wishes of Paul V. It was an "outlying structure, situated on the continuation of Borgo Nuovo toward Pius V tower, built in 1617-18 by Vasanzio and Ferabosco" (D. Gabbavotti Cravero, p. 283).

A plan of the square shows the fountain before the architect began work on it. Looking at the Basilica, this is the one on the right. It was placed in its present position by Bernini who, as instructed in minute detail by Alexander VII, shortly before his death in 1666, concluded the layout of the square by building, with the help of Mattia de' Rossi in 1667, the fountain on the left of the obelisk, similar to the one by Maderno, placing both on the diameter of the two ellipses but not in their centers which, as we have seen, are about half way between them and the obelisk.

The magnificence of the two fountains is partially attenuated by the vastness of the square. Almost eight meters high, they have an upper bowl made from a single block of oriental granite, 16 meters in circumference, on which a powerful jet of water falls, subsequently overflowing into the octagonal bowl beneath in travertine measuring approximately 30 meters in perimeter.

Bernini's Project

To complete Bernini's project, the third central arm of the colonnade should have been built. This work was unfortunately never completed, but we can see it in drawings which had already been approved by Alexander VII. Before the building of the second fountain, in the 1670s, Bernini also solved the difficult problem of joining the colonnade to the Basilica by means of two lateral corridors leaving a trapezoidal space in front of the façade.

The work was begun in 1660 with the demolition of the Ferabosco tower. The result, which today might seem obvious, takes into account the difficult visual relationship between the dome and the façade, solving it satisfactorily.

Bernini tried to attenuate the limiting effects on the front view of Michelangelo's work caused by the lengthening of the nave and by the imposing façade, of necessity with the same height. On the other hand, this was tied from the start to the size of the pillars and the relative arches supporting the dome.

The frieze on the façade bears the date 1612, the year of its inauguration. In reality, the grandiose prospect was uncovered on July 21 of that year, but two further years were required to finish it, thus arriving at 1614, over two and a half centuries after Pope Nicholas V (1447-1455) had decided, in the mid 15th century, to rebuild a new Basilica from the foundations upwards in place of Constantine's church.

Constantine's Church

The stability of Constantine's church was by then precarious in more than one point and which, above all, however venerable, no longer corresponded to the changed spirit of the times, brought by the Renaissance, and requiring a more grandiose building which could house a larger congregation.

The old church of St. Peter was over 1,000 years old and was beginning to show signs of decay, especially in the parts, such as the southern section, built on the ruins of the circus and other ancient buildings.

In fact, according to legend, the Emperor Constantine laid the foundations of the early Christian Basilica with five aisles, beginning the excavations himself and carrying 12 large baskets of earth, right in the place where Nero's Circus stood, between the Tiber, the Janiculum and Mons Vaticanus, where tradition had it that St. Peter was crucified and then buried.

St. Peter's Grave

This was a tradition borne out by all references subsequent to 200 A.D. and also by another even earlier one, by a learned Christian named Gaius, reported in a passage by the historian Eusebius (Hist. Eccl. 2.25.7). Gaius alluded to a rudimentary mausoleum built over the grave of the apostle, the so-called "memoria," that is a funeral monument with two rooms which, according to the Liber Pontificalis (the most ancient collection of biographies of the Roman Popes) had been built by the third Pope, St. Anacletus Martyr (76-88 A.D.) less than 30 years after the death of St. Peter.

In effect, right beneath the present Altar of Confession, a modest sepulchral complex called the "Trophy of Gaius" has come to light, which historians and, in part, archaeologists tend to identify with the one mentioned. At the same time, the exact location of Caligula's ancient circus, later to become Nero's, but already in disuse by the second century, has been established as parallel to the left plane of the Basilica.

The center of Nero's Circus was unquestionably fixed by the obelisk, now standing in the center of the square, which had remained in the circus from its erection there until it was moved in 1586. It was the custom of the ancient Romans to erect the altar of their Basilicas over the burial of the martyrs to whom they were dedicated; the sepulcher came to be an underground sanctuary, called "martyrion" by the Greeks and "fenestella confessionis" by the Romans, now called Confession.

In order to respect this custom, the builders of the Basilica, wishing to place the altar over the site of St. Peter's crucifixion and of his primitive burial, that is over Nero's circus, had to do an enormous amount of work to create a wide flat space around it. They had to demolish the circus, move many sepulchers and divert the Via Cornelia.

This task, evidently, was carried out to respect the requirements already mentioned and this too bears out the theory that the remains of the Apostle were to be found under the altar of the early Christian Basilica, and in consequence also under the present one.

Later, the invasions of the barbarians and subsequent sack by the Saracens in 846 induced the Popes to make the place increasingly less accessible, for reasons of security, until its complete isolation was achieved, quickly becoming surrounded by legend.

The Old Basilica

Begun by Emperor Constantine, the Old Basilica was finished by his son Constans just before 350 A.D. in a very short time. The speed of the work was made possible by a well laid out plan, and by a conspicuous number of incomes established by Constantine who, according to the Liber Pontificalis, had the venerated sarcophagus covered by a valuable casket and donated numerous rich gifts to the Basilica.

Constantine's Basilica, as many old drawings and engravings show us, was based on the horizontal type of early Christian Basilica, in turn, probably based on private Roman Basilicas, used as meeting rooms in patrician palaces and similar to other contemporary basilicas such as S. Giovanni in Laterano (St. John Lateran), S. Paolo fuori le Mura and S. Maria Maggiore (St. Paul outside the walls and St. Mary Major). Founded by Pope Liberius in 360 A.D., the latter is the only one to have conserved its original structure

The Old Basilica had a nave in which there were five parallel aisles cut in a Latin cross by a transept added by Pope Damasus who constructed the Baptistery in the outer right aisle. The roof was supported by 11 trusses, to which a gilded lacunar ceiling was fixed, but which soon was destroyed and was never replaced. In front of the church there was a large quadrangular space, called the Paradise atrium, enclosed by a four-sided portico supported by 46 columns, with at its center the Cantharus, formed by the bronze pine cone which can now be seen in the Vatican in the courtyard of the same name. Made in Roman times and found near Agrippa's thermae, it probably decorated a fountain near the Temple to Isis.

The atrium served to divide the square from the Basilica, and was reserved for the catechumens and to the penitents, who were not allowed to take part in the sacred rites.

The facade of the Basilica was much taller than the portico; from this it was possible to enter the church through five doors, the center three of which gave access to the central aisle. At the end of this was the "pergula," formed by 12 columns, with shafts spiraled like those of vines; these supported a silver beam from which lamps, crowns and gifts were hung. Behind the pergula, there was an apse or a presbytery.

The presbytery was a place dedicated to the veneration of St. Peter and of his sepulcher; on its back wall there was the Pope's chair and seats for the other important dignitaries. Before it was the altar, the only one in the church, placed under a canopy or "ciborium" and over the tomb. The vault of the apse was decorated with a mosaic.

Particularly important was also the "porticus pontificum" (pontifical portico), which was the side of the portico against the façade, thus called because for two and a half centuries from St. Leo I (?461) to Sergius I (?701) 34 Popes were buried there.

Before being demolished in several phases, as the work of the construction of the new one proceeded, in the course of 12 centuries, Constantine's Basilica had been continuously enriched, from the façade to the ceiling, from the walls to the chapel and the altars, and several important religious buildings had been erected outside.

Among these religious buildings erected over the centuries in which Constantine's Basilica was being terminated was St. Andrew's Oratory, formerly an imperial mausoleum and then called St. Mary of the Fever by reason of the venerated effigy of the Virgin Mary which Pope Symmachus (498-514) had transported there; St. John VII's Oratory named after the Pope who had it built (705-707), dedicated to the Virgin Mary and decorated with one of the most important mosaic works of the early Middle Ages in Rome and the Onoris Mausoleum, a round construction built at the beginning of the fifth century and then transformed into the St. Petronilla Chapel, when the remains of the saint were transferred there in 757 A.D. according to the wishes of Pepin the Short.

The St. Petronilla Chapel became particularly dear to the French sovereigns, so much so that it was better known as the "Capella regum Francorum." Additionally, both the fixed and mobile sacred ornaments in St. Peter's were continuously enriched not just by the Popes, but also by the kings and emperors, who came within its sacred walls, to be consecrated and crowned at the hand of the pontiffs.

Holy Roman Emperors

At Christmas of the year 800, Charlemagne was the first to be crowned by Leo III, who after greeting him with the name Charles August Great Pacific Emperor of the Romans, anointed him with the holy chrism and placed the sword upon him. After him, his successors Lothair and Louis II, and many others until Frederick III, received consecration before the tomb of the Apostle.

In St. Peter's, artistic embellishments of enormous value followed one another, right from the classical forms of the earliest period, when Christian art was being grafted onto the older pagan representations, through the Middle Ages, in which the tormented Carolingian conceptions and the refined Byzantine elegance were woven into the previous iconography, up until the 13th century when there was a revival of the rough skill of the Roman marble workers, softened by the arabesques of Arab decoration, while the vigorous art of Pietro Cavallini and Giotto's revolutionary techniques flourished, to arrive lastly in the 15th century with the construction of candid mausoleums and papal chapels by the great Tuscan masters.

Thus St. Peter's became a treasure chest containing an incalculably valuable wealth of works of art coming from the most varied sources, which were often subject to replacement. In the course of the centuries there were also renovations and so unfortunately these works have for the most part been either lost or destroyed.

In addition to the almost total loss of the paintings (the whole of the nave was decorated with them) and of the mosaics (of which the most important were those on the façade and on the apsidal vault), few of the various furnishings, and marble, wooden and bronze monuments have survived.

Some, like the Innocent VIII Sepulcher, the Filarete Door and a few columns, such as those twisted like vines from the Loggias of Relics, were transferred to the present Basilica; others are now in museums and other churches and a much larger number are in the Treasury and in the Vatican Grottoes. The disappearance of Constantine's Basilica was progressive. The still grandiose remains of the Medieval church ultimately disappeared in 1600 to make room for the final prolongation of the new Basilica, which at the Jubilee celebrations in 1600 welcomed 3 million pilgrims.

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