[Drawing] Lett[er]a d’Andrea Conero à Bernardo Rucellai in proposito dell’ Horolog[i]o Solare Antico Romano/ qui a lato designato.// Mag[nifi]co m[esser] Bernardo. Io ve mando con M[esser] hieronimo di Albici lo modello dello horologio antiquo lo quale si trova in/ Casa di certi Gentilhomeni Romani, chiamati della Valle, cosa per certo belliss[im]a. Esso horolog[i]o è di Marmo bianco et ha le figure di/ dodici segni celesti di rilievo, et così li quattro Cavalli, doi per banda, li doi quali non sono nel modello, sono in tutto simili à quelli, vi sono le parole di ciascuno Mese erano scritte sotto i signi, parte si leggono e parte sono guasti, come vederete/ nella Carta, dove sono scritte le parole empiano tutto de ciaschuno segno, et non come voi vedete le scritte appresso certi Segni nel Modello per Horologio [che] havete à fare. Vi mando Carte 4. Nella p[rim]a è la grandezza d’ esso horologio/ Nella 2a le figure a guardar iusto lo mezo di Levante, e mezodi. Nella 3a la figura a guardar iusto lo/ mezo fra Mezodi, et Ponente. Nella 4a la figura dello Cavo di esso horologio, e bisogna stia iusto verso Mezo/ di. A me non accade dare altra informatione, se non de quella parte, dove hanno a essere le figure del resto sequita/rete lo Modello p[raesert]tim di sop[r]a di sotto, cioè dove stanno li segni, e le scritture non accade sia coniunto con quel di sopra/ N’e ancora bisogna sia di marmo, e per niente vi metteresti scriver cosa niuna di sotto, cioe le quantità delli di, e/ delle Notti imitando lo antiquo, perche saria falso e torria la riputatione di esso Horologio. Nella Pa [i.e. prima] figura linea A.D. e la metà della larghezza dello horologio, e cosi viene a essere la meta della linea nella base/ la quale linea guarda verso mezodì, et è tirata da Levante à Ponenente[sic]. a.g. e la grandezza quanto à entrar/ lo cavo .f. e lo centro del cavo. f.g. è la grandezza con quale è scritto lo cavo. c.d. è equale. a.d. è la grandezza/ delle doe facce una tra Levante e Mezodi, l’altra tra Mezodi e Ponente. [?]C. h. è l’altezza del horo -/ logio h. k. è la sua grandezza che vene fora nella figura secundo a e loco dello gnomone a.b. è la grandezza di esso gnomone. Nella 3a similmente a. è il loco dello gnomone a.b. la grandezza di esso. Nella 4a a. loco del gnomone a.b. la grandezza di esso Ma ha d avvertire che/ l’horologio vostro sia di marmo bianco perché l’ombra si discerna melio. lo Concavo debbe essere descritto con grandezza di sesto, cioè cheI sesto che harà à descriverlo sia aperto secundo la linea f.g. della prima/ Carta, dove fosse altramente l’horologio verria falso [;] li gnomoni della seconda e 3a Carta debbano essere/ nelli loci predetti e perpendicolari sopra la soperficie della Carta. Quando sarà misso in figura nel cavo la linea/ dritta che si tirarà de e. ad. d. e partita per mezo li deve pervenire la extrémità del stilo cioè gnomone/ cioè b.// Le Linee Meridiane cioe nela figura 2a e 3a b.c. e ne la 4a a.c. direno essere perpendicolare/ sopra lo horizonte.//La figura che ha tirata certa linea ad un centro Darete a M[esser]Alexandro Pucci e ricomandandomi a S[ua]S[ignoria] [.] Altro non accade scrivere dove voi dubitarete scrivetemi, et io satisfarò per littere quanto/ sarà possibile, e no[n] dubbite che non habbiamo honore. Io so con quanta diligentia havia tirate le linee [.] a V[ostra] M[agnificen]cia mi racc[omman]do p[er]infinite volte la quale mi perdona se sono stato tardo[.] Romae/primo Septembris 1513./ Tutto di V[ostra] M[esser]. Andreas Conerus.// Nobili et Doct[issimo Viro D[omi]no/ Bernardo Oricellario tanq[uam]/ Patri honor[atissi]mo. Florentiae.// (‘Letter from Andreas Coner to Bernardo Rucellai on the subject of the ancient Roman sundial drawn here beside it.//Magnifico Messer Bernardo, I am sending you in the care of Girolamo degli Albizzi the modello [i.e. drawing] of the ancient sundial located in the house of certain Roman gentlemen called the Della Valle, [which is] without doubt a most beautiful thing. The sundial is made of white marble and bears the representations of twelve celestial signs [sculpted] in relief, as are the four horses, two on each side which are not shown in the drawing but are entirely similar to the other [reliefs]. There are the names for each month, which were written beneath the [celestial] signs, in part legible and in part damaged, as you will see on the drawing, in the place where the text fills the panel beneath each sign, and unlike the way the text accompanies certain of the signs in the sundial that you are having made. I send you four drawings [of this new sundial]. The first shows it as a whole. The second has drawings showing it facing southeast. The third shows it facing southwest. The fourth shows the design of the sundial’s [curved] recess, which needs to face precisely towards the south. I do not need to give you any further information except for the placement of the figures. You need to follow the scheme carefully in every part from top to bottom, and you need to make it in such a way that the inscriptions are not linked [?visually] with what is above. Furthermore, it needs to be made of marble, and you should not have inscribed underneath things such as the numbers of the days and nights in imitation of the Antique, because it would be false and would detract from the reputation of this sundial. In the first image, the line ‘A–D’ indicates half the width of the sundial, and so corresponds to half the line drawn from east to west along the base, which faces south. ‘A–G’ is the size of the concave recess. ‘F’ is the centre of the recess. ‘F–G’ is the measure with which the concave recess is inscribed. ‘C–D’ is equal. ‘A–D’ is the size of the two faces, one facing southeast and the other southwest. ‘C–H’ is the height of the sundial. ‘H–K’ indicates how far it projects forwards. In the second drawing ‘A’ is the position of the gnomon [i.e. pointer];[and] ‘A–B’ is the size of the gnomon [i.e. pointer]. In the third drawing likewise: ‘a’ is the position of the gnomon [i.e. pointer]; ‘a–b’ is the size of the gnomon [i.e. pointer]. In the fourth drawing: ‘A’ is the position of the gnomon [i.e. pointer]; ‘A–B’ is its size. It is important that your sundial should be of white marble so that the shadow may be more readily visible. The concavity must be drawn with an compass opened up so that it can trace a line equivalent to the line ‘F–G’ on the first sheet, or else the sundial will produce false readings. The gnomons [i.e. pointers] on the second and third sheets must be in the specified places and perpendicular to the surface to the paper [i.e the plan]; when it is put in place in the recess, the straight line that runs from ‘E’ to ‘D’ and is divided into two must reach the end of the stylus, or gnomon [pointer], which is ‘B’. The meridian lines, that is in the second and third drawings ‘B–C’, and in the fourth ‘A–C’, must be perpendicular above the horizon. Give the drawing that has a certain line leading to the centre to Messer Alessandro Pucci. And please commend me to his lordship. Nothing else occurs to me to mention, but if you have any questions write to me and I will answer by letter as far as I can; and be assured that we have done our best [in this] enterprise. I know just how much diligence was involved in making these drawings for your lordship. I commend myself to you an infinite number of times and ask you to excuse me if I am late [in sending them]. In Rome 1 September 1513. Yours Messer Andrea Coner.// To the noble and most learned lord Bernardo Rucellai most honoured father so to speak. In Florence’) [Verso] 43 [early seventeenth-century hand] [Mount] 47 [x2]

• c.1513/14
  Datable to c.1513/14

[Drawing] Pen and brown ink; on laid paper (232x167mm), stitching holes along right edge; rounded corners at left; inlaid (back-to-front with respect to original foliation, window on verso of mount) [Verso] Blank [Mount] Frame lines, in pen and dark brown ink, 10mm apart [Verso of mount] Window (223x159)

Unidentified scribe

[Drawing] None [Mount] Figure shown kneeling and holding a cross-topped staff set in a shield (variant 3; cut by bottom edge of window)

This is a copy of a letter about sundials, dated September 1513 and written by a certain Andreas Coner. A draft of this same letter, thought to in Coner’s own hand, has also come to light (Nesselrath 1992, pp. 160–66). The letter begins by discussing an ancient marble example owned by Rome’s Della Valle family and saying that a drawing of it was enclosed, almost certainly a version but not an exact duplicate of the one drawn on the next folio (Fol. 30r/Ashby 48), before describing its inscriptions and carvings in some detail. It then goes on to discuss a second sundial that was being made for the letter’s recipient, and four drawings of it that were also being sent. This modern sundial, which was presumably to be produced in Florence, was likewise to be made of marble, and the drawings for it, described here, indicate that it was going to be of comparable design, although seemingly with a gnomon, or pointer, on more than one side. The letter was no doubt reproduced in the compendium because it records a very recent engagement on the part of the recipient with the city of Rome and its ancient heritage.

Coner, a scholar based in Rome, was German by birth and seemingly a priest, and he died apparently in 1527 (Ashby 1904, pp. 3–4). Little else is known about him except that he had previously spent time in Venice and Mantua and had interests in mathematics and mechanical machinery (Nesselrath 1992, pp. 160–66), and that he appears to have known Fra’ Giocondo (Tura 1999). The letter implies that he was acting as a knowledgeable intermediary between the designer of the new sundial based in Rome and the those involved in its making based in Florence. The recipient of the letter was Bernardo Rucellai (1448–1514), the much-respected Florentine humanist – and ‘most honoured father so to speak’ – who was also the brother-in-law of Lorenzo de’Medici the Magnificent, and the uncle of Giovanni de’Medici, elected as Pope Leo X in 1513. That the letter was included in the codex suggests that Bernardo Rucellai had something to do with commissioning the compilation of drawings now known erroneously as the Codex Coner. He certainly had the right credentials. The son of Giovanni Rucellai, patron in Florence of the Rucellai palace and the façade of Santa Maria Novella, both designed by Leon Battista Alberti, he grew up fascinated by architecture ancient and modern, and he is known to have made architectural drawings himself as early as 1474 as well as writing a book about Rome’s antiquities – De urbe Roma – although this would remain unpublished in his lifetime (eventually issued in 1770). It is, therefore, hardly stretching the imagination to conclude that Rucellai was the intended recipient of the compilation of drawings and probably the patron of the whole enterprise, which was likely commenced after the accession of Leo X in March 1513 but abruptly curtailed by Rucellai’s death in October 1514. The subject of sundials was probably of particular fascination to Rucellai since he is known to have been interested in gadgetry, and this fascination may help explain why he approached Bernardo della Volpaia to compile the codex for him. Rucellai was certainly acquainted with the Della Volpaia family (Pagliara 1989c), a family renowned for producing timepieces and other instruments (Pagliara 1989c), and he may well have known that one of them was a draughtsman, surveyor and woodworker by profession who was closely linked to the leading architects in Rome of the time.

This version of the letter was clearly intended as a part of the compilation, rather than being inserted into it at some subsequent time. Although not in Bernardo della Volpaia’s hand, it was written on a sheet of paper that bore drawings by him on the other half of the double folio (Fols 29r/Ashby 47 and 30r/Ashby 48). It was originally written, moreover, on a verso (as indicated by the folio number being on the original recto) so it could face Bernardo’s drawing of the Della Valle sundial (Fol. 30r/Ashby 48). The sheet only became a recto when it was mounted in the seventeenth century. It was the presence of the letter in the original compilation that prompted Cassiano dal Pozzo to assume that Coner was the author of the drawings, and have his name written on the spine of the album. It caused Ashby at first to believe likewise (Ashby 1904, pp. 2–6), before he later changed his mind (Ashby 1913, pp. 189–90), the author’s name then remaining unknown until the 1970s when it was discovered by Tilmann Buddensieg.

Ashby 1904, pp. 32–33
Nesselrath 1992, pp. 160–66
Census, ID 44342

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.

If you have any further information about this object, please contact us: drawings@soane.org.uk