Humboldtians in Focus

Tracking Down Michelangelo

By Kristina Güroff

Since the 19th century, researchers have been allowed to use the Archives of the Fabric of St. Peter’s in Rome – and they certainly do use them. Yet, despite this, genuine treasures are still uncovered in the various archives at the Vatican and St. Peter’s. Just recently, art historian Vitale Zanchettin made a spectacular find.

Through the Porta at the Piazza del Sant’Uffizio, past the control point of the Swiss Guard, Vitale Zanchettin heads directly into the Vatican, enviously watched by the tourists – this is where the art historian works whenever he is conducting research in Rome: in the little Archivio della Fabbrica di San Pietro, the building lodge of St. Peter’s. It is located immediately above the arches of St. Peter’s Basilica and is reached by lift . As one of only four researchers allowed access to the archives each day, the procedure is always the same: sign your name in the archive’s register of users, swap your user’s identity card for a key to the cloakroom, take your place in the study area and sign in yet again. Vitale Zanchettin has been through all this innumerable times, when, on one particular Monday morning in October 2007, there is a momentous mix-up.

Zanchettin has just arrived from Bonn again to view documents he has already ordered. “Is this your file, Vitale?” the archivist asks. They know each other quite well after all this time. Zanchettin gives the ancient volume a cursory glance and says yes. For his research project he is searching the archive for documents on the history of the construction of St. Peter’s in the first years when Michelangelo (1475–1564) was in charge of construction work. One of the aims of his work is to describe the state of construction when Pope Paul III appointed Michelangelo as architect of St. Peter’s in succession to Bramante and Antonio de Sangallo the Younger. Zanchettin studies delivery lists, tries to identify blocks of stone in order to use the delivery data to reconstruct the progress of construction and draw general conclusions about construction management. What did they look like, those technical solutions Michelangelo discovered, what were the economic consequences of the alterations and what was the material consistency of the parts constructed?

12 x 22 cm – invaluable today, but just a disposable quantity for contemporaries: after his death, Michelangelo’s last known sketch to date was torn up and written on
12 x 22 cm – invaluable today,
but just a disposable quantity for
contemporaries: after his death,
Michelangelo’s last known
sketch to date was torn up and
written on.
Photo: courtesy of the Fabbrica
di San Pietro in Vaticano

On closer scrutiny it appears that the file is not the one Zanchettin has ordered, but he looks at it anyway because the documents from the building administration are interesting to him as well. Lying between more than 500 sheets he finds a small piece of paper that he would actually have put to the side quickly if he had not noticed lines sketched in red chalk in the shape of a curve which immediately catch his architectural expert’s attention. Masons’ red chalk or sanguine was popular for sketching and drafting because the mixture of clay and haematite can easily be rubbed out. Architects usually draw curves with a compass, but if they do not happen to have one with them on a construction site, for example, they can also use the most important natural compass there is, the human forearm. Zanchettin holds his arm over the page and – would you believe it – the proportions are just the same; his hand traces the thin line exactly! He immediately knows it must be an architect’s sketch. But who drew it? Could it be Michelangelo himself? Just how important such a find would be is obvious when one calls to mind a few figures: Michelangelo’s extant body of work comprises some 600 drawings of which only 20 are for St. Peter’s – despite the fact that Michelangelo was head architect there for 17 whole years.

Detective work in the Vatican

Vitale Zanchettin can rely on the staff at the archives to keep the fi le locked away until he has had an opportunity to examine all the facts. As mentioned above, people know each other quite well aft er all this time. Zanchettin starts investigating and three days later he is quite certain that he has discovered the fragment of a drawing by Michelangelo, probably even the very last one known to date.

Modern layer presentation of the place Michelangelo was indicating on the building of St. Peter‘s.
Modern layer presentation
of the place Michelangelo was
indicating on the building of
St. Peter's.
Photo: Simone Baldissini

The paper with the sanguine drawing is the torn-off corner of a roughly A3-sized sheet. On the one side there is a text in Italian which Zanchettin dates back to 1565, a year aft er Michelangelo’s death. It concerns a delivery of stones for the construction of St. Peter’s. The architect and his assistant were probably on the construction site and the assistant did not have any other paper with him. So he simply tore off a piece of an “old” sheet for rough paper to make his notes. The clerk at the fabric at St. Peter’s received the Italian note and, whether from lack of time or paper, simply wrote his version on what he assumed was the back, i.e. the side with the red chalk drawing. This official note in Latin was stored between the clerk’s documents and remained there in the Archives of the Fabbrica to this day.

“The manner of drawing shows Michelangelo’s threedimensional way of thinking and is closely related to our modern technology.”

The drawing shows a part of the plans of the architrave, a detail of the dome of St. Peter’s. According to Zanchettin, the script of some of the recognisable figures corresponds to Michelangelo’s own hand and he dates it back to 1563, one year before Michelangelo’s death. The drawing reveals quite a bit about the way Michelangelo worked: He obviously remained in direct contact with the stonemasons and the workers at the construction site right up to the end of his life. It is a very practical instruction as to how a certain travertine block should be cut and what form it should take on the inside of the wall – typical in its form for a sculptor who is used to supervising the quarrying and delivery of the stones. The manner of drawing clearly shows Michelangelo’s three-dimensional way of thinking and is closely related to our modern technology, the art historian reveals. The red chalk sketch is reminiscent of layer drawing, a concept employed in computer aided design for a layering technique used to improve the breakdown of complex graphic objects. This was very rare in the Renaissance but positively characteristic of Michelangelo.

Extended and minus the writing on top it emerges that Michelangelo was sketching how the stones should be cut for the architrave of the dome of St. Peter‘s.
Extended and minus the writing
on top it emerges that Michelangelo
was sketching how the stones
should be cut for the architrave of
the dome of St. Peter‘s.
Photo: Vitale Zanchettin

Having managed to establish that the drawing has not yet been published with the help of the Institute of Art History Library in Bonn and the Bibliotheca Hertziana in Rome, Zanchettin now turns to the leading experts in Renaissance research, including his host in Bonn, Georg Satzinger, to discuss his theories with them. Most of the researchers working on Renaissance architecture, and especially St. Peter’s, come from Germany. “The recognised language of scholarship in our research field is still German,” Satzinger emphasises. This is why Vitale Zanchettin is carrying out his current research project in Germany, although the vital sources on the construction history of St. Peter’s are to be found in Rome. Research traditions play an important role in the inventory of an institute. Thus it comes as no great surprise that Zanchettin compares the library in the Institute of Art History in Bonn to the Bibliotheca Hertziana and has discovered important leads for his investigations there. When he gets a positive response to his reasoning from the academics he has consulted, the sensation is complete. Following an internal presentation at the Vatican, the results are put before the public: On 7 December 2007, the “Osservatore Romano” reports the discovery of Michelangelo’s last known drawing to date. 

Together with his host, Zanchettin has already organised several excursions to Rome allowing Bonn students to profit from his knowledge of the field and the place. However, they should not ask him to recommend the best Caffè-Bar because Vitale Zanchettin prefers German filter coffee. But he can certainly be relied upon to show them the way into the Vatican through the Porta at the Piazza del Sant’Uffizio.


  • 29.10.2008 Jose Kallarackal

    Certainly very interesting to know how Michelangelo designed buildings in those days very similar to our present designs given by computer programs.

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Vitale Zanchettin Vitale Zanchettin

Dr. Vitale Zanchettin is art historian, who wrote his doctorate on the council housing designed by the German architect Ernst May. He teaches at Venice University Institute of Architecture. Since May 2007, he has been a guest researcher at the Institute of Art History at Bonn University on a Humboldt Fellowship.

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