The Life of Michelangelo Buonarroti

by John Addington Symonds

Michelangelo's reputation, not only as an imaginative builder, but also as a practical engineer in architecture, depends in a very large measure upon the cupola of S. Peter's. It is, therefore, of great importance to ascertain exactly how far the dome in its present form belongs to his conception. Fortunately for his reputation, we still possess the wooden model constructed under his inspection by a man called Giovanni Franzese. It shows that subsequent architects, especially Giacomo della Porta, upon whom the task fell of raising the vaults and lantern from the point where Michelangelo left the building, that is, from the summit of the drum, departed in no essential particular from his design. Della Porta omitted one feature, however, of Michelangelo's plan, which would have added greatly to the dignity and elegance of the exterior. The model shows that the entablature of the drum broke into projections above each of the buttresses. Upon these projections or consoles Buonarroti intended to place statues of saints. He also connected their pedestals with the spring of the vault by a series of inverted curves sweeping upwards along the height of the shallow attic. The omission of these details not only weakened the support given to the arches of the dome, but it also lent a stilted effect to the cupola by abruptly separating the perpendicular lines of the drum and attic from the segment of the vaulting. This is an error which could even now be repaired, if any enterprising Pope undertook to complete the plan of the model. It may, indeed, be questioned whether the omission was not due to the difficulty of getting so many colossal statues adequately finished at a period when the fabric still remained imperfect in more essential parts.

Vasari, who lived in close intimacy with Michelangelo, and undoubtedly was familiar with the model, gives a confused but very minute description of the building. It is clear from this that the dome was designed with two shells, both of which were to be made of carefully selected bricks, the space between them being applied to the purpose of an interior staircase. The dormer windows in the outer sheath not only broke the surface of the vault, but also served to light this passage to the lantern. Vasari's description squares with the model, now preserved in a chamber of the Vatican basilica, and also with the present fabric.

It would not have been necessary to dwell at greater length upon the vaulting here but for difficulties which still surround the criticism of this salient feature of S. Peter's. Gotti published two plans of the cupola, which were made for him, he says, from accurate measurements of the model taken by Cavaliere Cesare Castelli, Lieut.-Col. of Engineers. The section drawing shows three shells instead of two, the innermost or lowest being flattened out like the vault of the Pantheon. Professor Josef Durm, in his essay upon the Domes of Florence and S. Peter's, gives a minute description of the model for the latter, and prints a carefully executed copperplate engraving of its section. It is clear from this work that at some time or other a third semi-spherical vault, corresponding to that of the Pantheon, had been contemplated. This would have been structurally of no value, and would have masked the two upper shells, which at present crown the edifice. The model shows that the dome itself was from the first intended to be composed of two solid vaults of masonry, in the space between which ran the staircase leading to the lantern. The lower and flatter shell, which appears also in the model, had no connection with the substantial portions of the edifice. It was an addition, perhaps an afterthought, designed possibly to serve as a ground for surface-decoration, or to provide an alternative scheme for the completion of the dome. Had Michelangelo really planned this innermost sheath, we could not credit him with the soaring sweep upwards of the mighty dome, its height and lightness, luminosity and space. The roof that met the eye internally would have been considerably lower and tamer, superfluous in the construction of the church, and bearing no right relation to the external curves of the vaulting. There would, moreover, have been a long dark funnel leading to the lantern. Heath Wilson would then have been justified in certain critical conclusions which may here be stated in his own words. "According to Michelangelo's idea, the cupola was formed of three vaults over each other. Apparently the inner one was intended to repeat the curves of the Pantheon, whilst the outer one was destined to give height and majesty to the building externally. The central vault, more pyramidal in form, was constructed to bear the weight of the lantern, and approached in form the dome of the Cathedral at Florence by Brunelleschi. Judging by the model, he meant the outer dome to be of wood, thus anticipating the construction of Sir Christopher Wren." Farther on, he adds that the architects who carried out the work "omitted entirely the inner lower vault, evidently to give height internally, and made the external cupola of brick as well as the internal; and, to prevent it expanding, had recourse to encircling chains of iron, which bind it at the weakest parts of the curve." These chains, it may be mentioned parenthetically, were strengthened by Poleni, after the lapse of some years, when the second of the two shells showed some signs of cracking.

From Dr. Durm's minute description of the cupola, there seems to be no doubt about the existence of this third vault in Michelangelo's wooden model. He says that the two outer shells are carved out of one piece of wood, while the third or innermost is made of another piece, which has been inserted. The sunk or hollow compartments, which form the laquear of this depressed vault, differ considerably in shape and arrangement from those which were adopted when it was finally rejected. The question now remains, whether the semi-spherical shell was abandoned during Michelangelo's lifetime and with his approval. There is good reason to believe that this may have been the case: first, because the tambour, which he executed, differs from the model in the arching of its windows; secondly, because Fontana and other early writers on the cupola insist strongly on the fact that Michelangelo's own plans were strictly followed, although they never allude to the third or innermost vault. It is almost incredible that if Della Porta departed in so vital a point from Michelangelo's design, no notice should have been taken of the fact. On the other hand, the tradition that Della Porta improved the curve of the cupola by making the spring upward from the attic more abrupt, is due probably to the discrepancy between the internal aspects of the model and the dome itself. The actual truth is that the cupola in its curve and its dimensions corresponds accurately to the proportions of the double outer vaulting of the model.

Taking, then, Vasari's statement in conjunction with the silence of Fontana, Poleni, and other early writers, and duly observing the care with which the proportions of the dome have been preserved, I think we may safely conclude that Michelangelo himself abandoned the third or semi-spherical vault, and that the cupola, as it exists, ought to be ascribed entirely to his conception. It is, in fact, the only portion of the basilica which remains as he designed it.

CHAPTER XIV

I

There is great difficulty in dealing chronologically with the last twenty years of Michelangelo's life. This is due in some measure to the multiplicity of his engagements, but more to the tardy rate at which his work, now almost wholly architectural, advanced. I therefore judged it best to carry the history of his doings at S. Peter's down to the latest date; and I shall take the same course now with regard to the lesser schemes which occupied his mind between 1545 and 1564, reserving for the last the treatment of his private life during this period.

A society of gentlemen and artists, to which Buonarroti belonged, conceived the plan of erecting buildings of suitable size and grandeur on the Campidoglio. This hill had always been dear to the Romans, as the central point of urban life since the foundation of their city, through the days of the Republic and the Empire, down to the latest Middle Ages. But it was distinguished only by its ancient name and fame. No splendid edifices and majestic squares reminded the spectator that here once stood the shrine of Jupiter Capitolinus, to which conquering generals rode in triumph with the spoils and captives of the habitable world behind their laurelled chariots. Paul III. approved of the design, and Michelangelo, who had received the citizenship of Rome on March 20, 1546, undertook to provide a scheme for its accomplishment. We are justified in believing that the disposition of the parts which now compose the Capitol is due to his conception: the long steep flight of steps leading up from the Piazza Araceli; the irregular open square, flanked on the left hand by the Museum of Sculpture, on the right by the Palazzo dei Conservatori, and closed at its farther end by the Palazzo del Senatore. He also placed the equestrian statue of Marcus Aurelius Antoninus on its noble pedestal, and suggested the introduction of other antique specimens of sculpture into various portions of the architectural plan. The splendid double staircase leading to the entrance hall of the Palazzo del Senatore, and part of the Palazzo dei Conservatori, were completed during Michelangelo's lifetime. When Vasari wrote in 1568, the dead sculptor's friend, Tommaso dei Cavalieri, was proceeding with the work. There is every reason, therefore, to assume that the latter building, at any rate, fairly corresponds to his intention. Vignola and Giacomo della Porta, both of them excellent architects, carried out the scheme, which must have been nearly finished in the pontificate of Innocent X. (1644-1655).

Like the cupola of S. Peter's, the Campidoglio has always been regarded as one of Michelangelo's most meritorious performances in architecture. His severe critic, M. Charles Garnier, says of the Capitol: "The general composition of the edifice is certainly worthy of Buonarroti's powerful conception. The balustrade which crowns the façade is indeed bad and vulgar; the great pilasters are very poor in invention, and the windows of the first story are extremely mediocre in style. Nevertheless, there is a great simplicity of lines in these palaces; and the porticoes of the ground-floor might be selected for the beauty of their leading motive. The opposition of the great pilasters to the little columns is an idea at once felicitous and original. The whole has a fine effect; and though I hold the proportions of the ground-floor too low in relation to the first story, I consider this façade of the Capitol not only one of Michelangelo's best works, but also one of the best specimens of the building of that period. Deduction must, of course, be made for heaviness and improprieties of taste, which are not rare."