To an approximate scale of 1:375

[Drawing] HICNOGRAPHIA. PANTHEONIS./ .IDEST. S. MARIAE. ROTVNDAE. (Plan of the Pantheon, that is Santa Maria Rotunda); Vacuu[m]. est. b. 73. mi[nuti]. 33 (‘The space is 73 braccia and 33 minutes’); hic. corona. exit/ .ob. diminuitionem/ colonna[rum]. (‘This cornice protrudes owing to the diminution of the columns’); totum. est b. 59. minuta. 36 (‘The whole is 59 braccia and 36 minutes’); [numerous measurements]; 8 [early seventeenth-century hand)
[Mount] 13 [x2]

• c.1513/14
  Datable to c.1513/14

[Drawing] Pen and brown ink and grey-brown wash; on laid paper (232x164mm), rounded corners at right, inlaid (window on verso of mount)
[Mount] Frame lines, in pen and dark brown ink, 10mm apart

Bernardo della Volpaia

[Drawing] None [Mount] None

The Pantheon was the most celebrated of all ancient temples – whether genuine or presumed – and was designed in the form of an enormous domed rotunda, the largest from antiquity, with a pedimented portico attached to its front. Located in the Campus Martius around a kilometre northwest of the Roman Forum, it replaced a previous building of the same name originally built by Agrippa in the late first century BCE, and was rebuilt under the Emperor Hadrian (LTUR 1993–2000, 4, pp. 54–61), although the reconstruction, well underway by 123 CE, was perhaps begun around 114 CE under Trajan (see Hetland 2007 and 2015). This plan of the building is identified by a caption, in all’antica capitals, which then adds for the sake of clarity that the building was now the church known as Santa Maria Rotonda, the popular sobriquet it received after its consecration in 608 CE as Santa Maria ad Martyres. It shows the building in its original condition, without the ciborium and high altar recently installed in the end apse by Pope Innocent VIII (r.1484–92), which are recorded in a plan by Hermann Vischer the Younger of 1515 (Nesselrath 2015b, pp. 267–70). In that sense, therefore, it is a reconstruction, although one that involved stripping away later accretions rather than reimagining features that were missing.

The Coner drawing also charts an important stage in the increasing accuracy and understanding of the building. Earlier plans were in part hypothetical reconstructions, since, with the change in ground level since Roman times, the lower parts of the building’s exterior were buried and thus invisible. The plan by Giuliano da Sangallo in the Codex Barberini shows the building raised on a platform of nine steps that run all the way around the exterior, while the one in the Codex Escurialensis, plus another attributed to Baccio d’Agnolo, have it on a platform of seven steps that is limited to the front and sides of the portico. The Coner drawing, by contrast, shows only what could be seen, which was the columns but no steps, the latter eventually revealed to be at least five in number and confined to the building’s front (De Fine Licht 1968, fig. 105). The drawing also marks an advance on earlier representations in the arrangement of the stairwells at the rear of the portico, by showing two spaces, symmetrically disposed either side of the entrance, rather than just one as represented by the Codex Barberini and Codex Escurialensis plans. While it follows the earlier tradition of representing the stairwell on the left incorrectly as triangular in plan, some attempt is made to correct this error in the treatment of the right-hand stairwell, which has been amended to conform much more closely to the trapezoidal shape the stairwell has in reality. The correct arrangement of the staircases is first seen in a slightly later drawing from c.1519 in Vienna. What is evident in the Coner plan as elsewhere in the codex, therefore, is a strategy of using previous depictions but modifying them where they were clearly erroneous.

A further difference from the earlier plans is that the Coner drawing records the niches inside the semi-circular and rectangular exedrae of the interior. Although some of these niches are already indicated in a plan by Francesco di Giorgio, they only became standard features of Pantheon plans in the wake of the Codex Coner. Among the drawing’s oddities, however, are the treatments of the first two tabernacles to the left of the entrance, which are represented differently from the others – one without its framing columns and the other blocked out completely with wash – although these discrepancies may just be drafting errors. The building is also shown without the bath building now known as the Basilica of Neptune attached to its rear, which, again, is first seen in the drawing in Vienna.

The inscription on the right of the portico, specifying that the cornice protrudes ‘owing to the diminution of the columns’, deals with the fact that the portico columns taper towards their tops unlike the respondent pilasters, which have parallel sides, and are thus wider at their tops than the columns, and so may require the entablature to project accordingly. This is the earliest known recognition of this ancient design feature (on which see Davies–Hemsoll 1992), and several similar observations would be made soon afterwards about other buildings (see Zampa 2019, pp. 23–26).

The drawing gives the diameter of the interior as 73 braccia and 33 minutes (42.9m), which differs slightly from the measurements on other early drawings, and suggests it was the result of one of many early measuring campaigns, although this one, to judge from the numerous measurements here and on the other Pantheon drawings in the album, was exceptionally comprehensive. The Codex Barberini drawing puts the diameter at 75 braccia, an early drawing by Peruzzi reckons it at 64 braccia 16 minutes, one by Raffaello da Montelupo in his Lille Sketchbook makes it 73 braccia and 15½ minutes, and one in Florence’s Biblioteca Nazionale gives it as 74 braccia and 6 ‘oncie’. The actual diameter, measured to the faces of the surrounding pilasters, comes to 43.45m (Wilson Jones 2000, p. 184).

OTHER IMAGES MENTIONED: [Francesco di Giorgio] Turin, Biblioteca Reale, Codex Saluzziano 148, addendum, fol. 79v (Maltese 1967, 1, p. 280); [Giuliano da Sangallo] Rome, BAV, Barb. lat. 4424 (Codex Barberini), fol. 13r (Hülsen 1910, 1, p. 23; Borsi 1985, p. 94); [Anon.] El Escorial, Real Monasterio, 28-II-12 (Codex Escurialensis), 71r (Egger 1905–06, p. 160); [Baccio d’Agnolo, attr.] Florence, GDSU, 4379 Ar (Bartoli 1914–22, 6, p. 6); [Italian Draughtsman A] Florence, BNC, Inv. II I 429, fol. 1r; [Raffaello da Montelupo, attr.] Lille, Musée des Beaux Arts, Lille Sketchbook, fol. 52v/no. 802 (Lemerle 1997, p. 306); [Baldassare Peruzzi] Florence, GDSU, 462 Ar (Bartoli 1914–22, 6, p. 56; Wurm 1984, pl. 475); [Anon. Italian C of 1519] Vienna, Albertina, inv. Egger no. 6v (Egger 1903, p. 18; Valori 1985, pp. 95–97; Günther 1988, p. 340 and pl. 29b)

OTHER DRAWINGS IN CODEX CONER OF SAME SUBJECT: Fol. 23r/Ashby 35; Fol. 23v/Ashby 36; Fol. 24r/Ashby 37; Fol. 24v/Ashby 38; Fol. 38r/Ashby 61; Fol. 38v/Ashby 62; Fol. 39r/Ashby 63; Fol. 40r/Ashby 65; Fol. 50v/Ashby 86; Fol. 65r/Ashby 111)

Ashby 1904, p. 16
Ashby 1913, p. 191
Census, ID 43438

Drawing

Digitisation of the Codex Coner has been made possible through the generosity of the Census of Antique Works of Art and Architecture Known in the Renaissance, Berlin

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