Michelagnolo by this time was reduced to a feeble condition, and it was evident that little was being done in S. Pietro, now that he had carried on a great part of the frieze of the windows within, and of the double columns without, which curve above the great round cornice[4] where the cupola is to be placed, as will be related; and he was exhorted and urged by his greatest friends, such as the Cardinal of Carpi, Messer Donato Giannotti, Francesco Bandini, Tommaso de' Cavalieri, and Lottino that, since he saw the delay in the raising of the cupola, he should at least make a model of it. He stayed many months without making up his mind to this, but in the end he made a beginning, and then little by little constructed a small model in clay, from which, as an exemplar, and from the plans and profiles that he had drawn, it might be possible afterwards to make a larger one of wood. This, having made a beginning with it, he caused to be constructed in little more than a year by Maestro Giovanni Franzese, with much study and pains; and he made it on such a scale that the smaller proportions of the model, measured by the old Roman palm, corresponded with complete exactness to those of the large work, he having fashioned with diligence in that model all the members of columns, bases, capitals, doors, windows, cornices, projections, and likewise every least thing, knowing that in such a work no less should be done, for in all Christendom, nay, in all the world, there is not to be found or seen any fabric more ornate or more grand. And I cannot but think that, if we have given up time to noting smaller things, it is even more useful, and also our duty, to describe this manner of design for building the structure of this tribune with the form, order, and method that Michelagnolo thought to give it; wherefore with such brevity as we may we will give a simple description of it, to the end that, if it should ever be the fate of this work, which God forbid, to be disturbed by the envy and malice of presumptuous persons after the death of Michelagnolo, even as we have seen it disturbed up to the present during his lifetime, these my writings, such as they may be, may be able to assist the faithful who are to be the executors of the mind of that rare man, and also to restrain the malignant desires of those who may seek to alter it, and so at one and the same time assist, delight, and open the minds of those beautiful intellects that are the friends of this profession and regard it as their joy.

S. PETER'S
(After Michelagnolo. Rome)
Anderson
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I must begin by saying that according to this model, made under the direction of Michelagnolo, I find that in the great work the whole space within the tribune will be one hundred and eighty-six palms, speaking of its width from wall to wall above the great cornice of travertine that curves in a round in the interior, resting on the four great double piers that rise from the ground with their capitals carved in the Corinthian Order, accompanied by their architrave, frieze, and cornice, likewise of travertine; which great cornice, curving right round over the great niches, rests supported upon the four great arches of the three niches and of the entrance, which form the cross of the building. Then there begins to spring the first part of the tribune, the rise of which commences in a basement of travertine with a platform six palms broad, where one can walk; and this basement curves in a round in the manner of a well, and its thickness is thirty-three palms and eleven inches, the height to the cornice eleven palms and ten inches, the cornice over it about eight palms, and its projection six and a half palms. Into this basement you enter, in order to ascend the tribune, by four entrances that are over the arches of the niches, and the thickness of the basement is divided into three parts; that on the inner side is fifteen palms, that on the outer side is eleven palms, and that in the centre is seven palms and eleven inches, which make up the thickness of thirty-three palms and eleven inches. The space in the centre is hollow and serves as a passage, which is two squares in height and curves in a continuous round, with a barrel-shaped vault; and in line with the four entrances are eight doors, each of which rises in four steps, one of them leading to the level platform of the cornice of the first basement, six palms and a half in breadth, and another leading to the inner cornice that curves round the tribune, eight palms and three-quarters broad, on which platforms, by each door, you can walk conveniently both within and without the edifice, and from one entrance to another in a curve of two hundred and one palms, so that, the sections being four, the whole circuit comes to be eight hundred and four palms. We now have to ascend from the level of this basement, upon which rest the columns and pilasters, and which forms the frieze of the windows within all the way round, being fourteen palms and one inch in height, and around it, on the outer side, there is at the foot a short order of cornice-work, and so also at the top, which does not project more than ten inches, and all of travertine; and so in the thickness of the third part, above that on the inner side, which we have described as fifteen palms thick, there is made in every quarter-section a staircase, one half of which ascends in one direction and the second half in another, the width being four palms and a quarter; and this staircase leads to the level of the columns. Above this level there begin to rise, in line with the solid parts of the basement, eighteen large piers all of travertine, each adorned with two columns on the outer side and pilasters on the inner, as will be described below, and between the piers are left the spaces where there are to be all the windows that are to give light to the tribune. These piers, on the sides pointing towards the central point of the tribune, are thirty-six palms in extent, and on the front sides nineteen and a half. Each of them, on the outer side, has two columns, the lowest dado of which is eight palms and three-quarters broad and one palm and a half high, the base five palms and eight inches broad and ... palms and eleven inches high, the shaft of the column forty-three and a half palms high, five palms and six inches thick at the foot and four palms and nine inches at the top, the Corinthian capital six palms and a half high, with the crown of mouldings nine palms. Of these columns three quarters are to be seen, and the other quarter is merged into the corner, with the accompaniment of the half of a pilaster that makes a salient angle on the inner side, and this is accompanied in the central inner space by the opening of an arched door, five palms wide and thirteen palms and five inches high, from the summit of which to the capitals of the pilasters and columns there is a filling of solid masonry, serving as a connection with two other pilasters that are similar to those that form a salient angle beside the columns. These two pilasters correspond to the others, and adorn the sides of sixteen windows that go right round the tribune, each with a light twelve palms and a half wide and about twenty-two palms high. These windows are to be adorned on the outer side with varied architraves two palms and three-quarters high, and on the inner side they are to be adorned with orders likewise varied, with pediments and quarter-rounds; and they are wide without and more narrow within, and so, also, they are sloped away at the foot of the inner side, so that they may give light over the frieze and cornice. Each of them is bordered by two flat pilasters that correspond in height to the columns without, so that there come to be thirty-six columns without and thirty-six pilasters within; over which pilasters is the architrave, which is four palms and three-quarters in height, the frieze four and a half, and the cornice four and two-thirds, with a projection of five palms; and above this is to go a range of balusters, so that one may be able to walk all the way round there with safety. And in order that it may be possible to climb conveniently from the level where the columns begin, another staircase ascends in the same line within the thickness of the part that is fifteen palms wide, in the same manner and of the same width, with two branches or ascents, all the way up to the summit of the columns, with their capitals, architraves, friezes, and cornices; insomuch that, without obstructing the light of the windows, these stairs pass at the top into a spiral staircase of the same breadth, which finally reaches the level where the turning of the tribune is to begin.

All this order, distribution, and ornamentation is so well varied, commodious, rich, durable, and strong, and serves so well to support the two vaults of the cupola that is to be turned upon it, that it is a very ingenious thing, and it is all so well considered and then executed in masonry, that there is nothing to be seen by the eyes of one who has knowledge and understanding that is more pleasing, more beautiful, or wrought with greater mastery, both on account of the binding together and mortising of the stones and because it has in it in every part strength and eternal life, and also because of the great judgment wherewith he contrived to carry away the rain-water by many hidden channels, and, finally, because he brought it to such perfection, that all other fabrics that have been built and seen up to the present day appear as nothing in comparison with the grandeur of this one. And it has been a very great loss that those whose duty it was did not put all their power into the undertaking, for the reason that, before death took away from us that rare man, we should have seen that beautiful and terrible structure already raised.

Up to this point has Michelagnolo carried the masonry of the work; and it only remains to make a beginning with the vaulting of the tribune, of which, since the model has come down to us, we shall proceed to describe the design that he has left to the end that it may be carried out. He turned the curve of this vault on three points that make a triangle, in this manner:

A B
C

The point C, which is the lowest, is the principal one, wherewith he turned the first half-circle of the tribune, with which he gave the form, height and breadth of this vault, which he ordered to be built entirely of bricks well baked and fired, laid herring-bone fashion. This shell he makes four palms and a half thick, and as thick at the top as at the foot, and leaving beside it, in the centre, a space four palms and a half wide at the foot, which is to serve for the ascent of the stairs that are to lead to the lantern, rising from the platform of the cornice where there are balusters. The arch of the interior of the other shell, which is to be wider at the foot and narrower at the top, is turned on the point marked B, and the thickness of the shell at the foot is four palms and a half. And the last arch, which is to be turned in order to make the exterior of the cupola, wider at the foot and narrowing towards the top, is to be raised on the point marked A, which arch turned, there remains at the top all the hollow space of the interior for the ascent of the stairs, which are eight palms high, so that one may climb them upright; and the thickness of that shell comes to diminish little by little, insomuch that, being as before four palms and a half at the foot, it decreases at the top to three palms and a half. And the outer shell comes to be so well bound to the inner shell with bonds and with the stairs, that the one supports the other; while of the eight parts into which the fabric is divided at the base, the four over the arches are left hollow, in order to put less weight upon the arches, and the other four are bound and chained together with bonds upon the piers, so that the structure may have everlasting life.

The stairs in the centre between one shell and the other are constructed in this form; from the level where the springing of the vault begins they rise in each of the four sections, and each ascends from two entrances, the stairs intersecting one another in the form of an X, until they have covered the half of the arch marked C, on the upper side of the shell, when, having ascended straight up the half of that arch, the remaining space is then easily climbed circle after circle and step after step in a direct line, until finally one arrives at the eye of the cupola, where the rise of the lantern begins, around which, in accord with the diminution of the compartments that spring above the piers, there is a smaller range of double pilasters and windows similar to those that are constructed in the interior, as will be described below.