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Slide Sets |
Slide Set #29:
Gregorio Dati's Sfera and Geographical Education in Fifteenth-Century Florence
commentary by Raymond Clemens (Illinois State University)
© 2002, The Newberry Library
This slide set, in its printed and virtual formats, was produced by a participant in "Popular Cartography and Society" a summer institute organized by the Hermon Dunap Smith Center for the History of Cartography at the Newberry Library in 2001. The institute was supported in part by the National Endowment for the Humnaities. Any views, findings, conclusions, or recommendations expressed in this publication/website do not necessarily reflect those of the National Endowment for the Humanities.
| La Sfera |
| La Sfera (The Spheres) is a pedagogical text composed in ottava rima (eight stanzas with ABABABCC rhyme structure) designed to instruct students in the astronomic and geographic sciences. La Sfera is divided into four equal parts, or books, each of which details a distinct aspect of geography, from macrocosm (the cosmos) to microcosm (the earth), concluding with maps of the terrestrial world as fifteenth-century Florentines understood and traveled it. Book One concerns cosmography and astrology; Book Two explains earthly phenomena such as winds, weather, and seasons; Book Three demonstrates the use of a compass, timekeeping and navigation; and Book Four provides a description of the shorelines of the southern and eastern Mediterranean and the Black Sea. Marginal illuminations accompanying the text include depictions of the earth, diagrams explaining solar and lunar eclipses, and fragmented maps based on portolan charts (early navigational maps depicting the shoreline of the Mediterranean and Black Sea with port cities prominently marked). Dati’s Sfera may be the first geographical primer in Western history; it was certainly the first that could be used by the autodidact. The rhymed text and the elaborate cycle of illustration might have facilitated memorization. While not exhaustive in its treatment of astronomy and geography, the Sfera did provide the educated Florentine merchant fundamental geographical information such as the distances between ports along the coastline of the Mediterranean and the basic information needed to understand cosmographical events (solar and lunar eclipses, the movement of the planets, etc.). That the Sfera filled this need admirably is witnessed by the survival of more than 200 manuscripts in European and North American libraries, making it one of the most copied geographical texts during the fifteenth and sixteenth centuries. Because it was a pedagogical work and such manuscripts often saw intensive and destructive use, the survival of so many manuscripts is even more impressive. The Sfera lost popularity in the sixteenth century perhaps because the world as Europeans knew it expanded significantly after the late fifteenth century, and Dati’s maps no longer accurately portrayed the world the Europeans knew and traveled. It was printed in Florence, but only three of the printed copies survive (at the Bibliothèque Nationale in Paris, the Vatican Library, and the Henry E. Huntington Library, San Marino). |
| Authorship |
Most scholars agree that La Sfera was written by Gregorio Dati (1362-1435), a Florentine merchant who rose from humble beginnings, the grandson of a purse vender, to a position of prominence in the city council, eventually appointed Standard Bearer of Justice, the highest civic office in Florence, in 1429. Some manuscripts of the Sfera attribute the work to Gregorio’s brother Leonardo (1360-1425), a Dominican friar who became Master General of the order, but most scholars agree this is a false attribution. Although Leonardo was well known as an author of sermons and commentaries on Aristotle, what survives of his works is written in Latin. In addition to the Sfera, Gregorio is also the author of the History of Florence 1380-1406, a chronicle of Florence’s war with Giangaleazzo written in Italian. We also know a great deal about Gregorio’s life from a register he kept (a ricordanze) in which he recorded various business and personal information. This was a common practice in Renaissance Florence, and such books were often called libri segreti (secret books) to distinguish them from official business registers; they were often beautifully bound in brilliantly dyed leather covers that were color coded to distinguish the public from the private and various years and business ventures. From Gregorio’s ricordanze (translated by Martines, see bibliography), we know that he was a silk merchant with extensive international contacts who often traveled across the western Mediterranean to conduct business in Spain. After the death of his first wife in 1390, he lived in Valencia for two years, where he sired a son with a Tartar slave named Maria. He sent his son, whom he named Thomas, back to Florence. The journal reveals that in 1393, Gregorio set out for Valencia again but was set upon by pirates from Briganzone near the Riviera (outside of Genoa). He lost personal assets including pearls, merchandise and clothing valued at 250 florins and company merchandise valued at 300 florins. He alludes to this event in his Sfera, where he writes:
And with a chart on which are marked the winds and ports and all the coastlines, merchants and pirates sail the sea — one for profit, the other for plunder. And in an instant the rich and unlucky know, sometimes in the evening and sometimes in the morning, that Fortune in any other thing does not show herself so ruinous.At the end of his ricordanze, we learn that Gregorio had twenty children (ten boys and ten girls) by three different wives; each of his wives and all but five of his children had predeceased him by 1427 (the last year Gregorio recorded his affairs in the ledger). That Gregorio had an interest in education is clear from his Florentine history, which describes the development of its unique governing structure in great detail. The Sfera was yet another way to communicate vital information to his fellow citizens. |
| Missing Maps |
| There is a question as to whether Dati intended to end the Sfera at Book 4, which only treats the southern half of the Mediterranean from the straits of Gibraltar as far north as the Black Sea, or if he envisioned continuing the treatise to complete the northern shoreline of the Mediterranean. If the Sfera as we know it represents the completed book, why did he not treat the coast of Italy: did he assume his reader would already know Italian and southern European geography and therefore have no need to review it? Dati’s work as it stands has a quadripartite structure; the composition of additional chapters would have devoted more space to the Mediterranean than to any other part of his book. Regardless of Dati’s intentions, at least one individual felt it necessary to continue the Sfera; in 1514, Giovanni Maria Tolosani published two supplements to complete the circle of the Mediterranean. |
| Attributes of Ayer MS map 1 |
| The manuscript of Dati’s Sfera in the Newberry Library’s collections (Ayer MS Map 1) dates from the fifteenth century. It is written in humanist rotunda, a book hand notable for its legibility. There are few ligatures or abbreviations in the manuscript, an indication that the book was prized as much for its appearance as for its utility. There is a coat of arms, as yet unidentified, on the front page of the work, indicating that this manuscript was copied for a particular individual. Based on an examination of the codex, we can be sure that the Newberry Sfera was composed in the manner typical for the fifteenth century: the text was copied first, followed by the initial letters in blue; then the marginal summaries were written, and finally the vinestem illumination and maps themselves were drawn. The Newberry Sfera is creased down the middle, indicating that the manuscript was almost certainly folded and carried in a pocket, consistent with its use for instruction.
Each folio contains three or four stanzas of text oriented to the top and gutter (center margin) of the book, leaving wide margins on the outside and bottom for a series of illustrations. Although not every copy of the Sfera is illustrated, there is little doubt that Dati intended for his Sfera to be accompanied by the diagrams found in the margins; he makes direct references to the illustrations in the text, and all the copies that contain images do so in the same order even if certain illustrations are omitted. The Newberry Sfera contains the full program of illustrations, and the illuminator has made an effort to place each map on the same page as the accompanying text, and, strikingly, to integrate text and image by extending the image into the text. Note, for example, f. 15v (slide 4), in which the illuminator has submerged several stanzas under the Mediterranean, and the scribe has extended the image across the page opening, a rare and difficult feat in medieval manuscripts because they were usually illustrated before they were bound together, making it extremely difficult to align the two halves of the image. The images themselves are compelling. The cosmographical illustrations in Books One through Three show the traditional earth-centered view of the cosmos. Dati’s maps of the earth are based on the traditional T/O map (that is, a diagram in which the world is divided into three parts resembling the capital letter “T” inscribed in a capital letter “O”) found in Isidore of Seville’s Etymologiarum and De natura rerum. Isidore was a seventh-century Spanish bishop who compiled several encyclopedic works. One can see Dati’s didactic intention in his verbal description recalling the written image:The drawing of a T inside an O shows how the world was divided into three parts, and the upper and larger realm, which takes almost half the circle, is called Asia; the straight leg, the sign that separates the third name from the second, separates Africa from Europe. The Mediterranean Sea appears in the middle between them [that is, the stem of the T].His map of the Middle East is similar to earlier mappamundi (medieval world maps) that depict Jerusalem at the center of the earth. In Book Four, where Dati describes the coast of the Mediterranean from the Canary Islands in the Atlantic to the Black Sea along the coast of Northern Africa, his source seems to have been portolan charts used to navigate the Mediterranean; the coastlines are accurately represented, and the port cities are more often depicted than inland cities. What is original to Dati’s Sfera is the fragmenting of these portolan charts and their employment for pedagogical rather than nautical purposes. There is a remarkable variation in the style of the illuminations from one Dati manuscript to another, indicating, perhaps, a greater freedom given to the copier of the images than the copier of the text. In some manuscripts, the movement of the seas is conveyed through long hair-like patterns with various eddies. The scribe of the Newberry Sfera uses faint lines to indicate water movement, but prefers color to indicate depth — the seas are dark green where they touch land and gradually fade as they become more distant from the shoreline. The images in this set were chosen to demonstrate the many types of information that Dati presented in his Sfera. |
| Cosmos: Ayer MS map 1, f, 1v (Image 1) |
 Dati’s Sfera opens with a prayer to God, creator and ruler of the cosmos. The first illumination depicts the heavens with the moving celestial spheres, including the sun, moon, planets and stars. The illuminator has represented motion using streaks of darker blue to indicate the rotation of the stars and planets as they circle the earth. Depictions of heavens from an earthly perspective in realistic fashion are relatively rare in medieval manuscripts; Dati’s source may have been Ptolemy’s Almagest, translated from Greek into Latin around 1406, by Jacobus Angelus. |
| Zodiac, Spheres: Ayer MS map 1 f. 2v (Image 2) |
 Here Dati describes the spheres not as they appear from earth (as in Image 1), but from a more traditional heavenly perspective. The image in the upper left corner represents the signs of the Zodiac: Aries, Taurus, Gemini, Cancer, Leo, and Virgo in the order they are visible from the earth (the round circle behind the Zodiac). The circle on the bottom represents the spheres that surround the earth: Terra (earth itself), Aqua, Aria, Fuoco, Luna, Mercurio, Venus, Sole, Marti, Jove, Saturno (land, water, air, fire, the moon, Mercury, Venus, the sun, Mars, Jove, Saturn). The elements can be distinguished by their colors (brown, green, blue, and red), and the planets are represented by stars. |
| World: Ayer MS map 1, f, 14v (Image 3) |
 This page displays two representations of the earth (terra), one in a diagram and one that is more realistic. Both are maps of the earth’s surface. At the top is the Isidorian T-O map, so called because it was first found in Isidore of Seville’s Etymologiarum sive originum libri XX (622-633) and De natura rerum (612-615). It represents the earth divided into three landmasses: Asia (clearly dominant), Europe, and Africa. Dati was the first to describe Isidore’s world map as a “T-O” map, an example of his didactic intention (see text above). Immediately below the T-O map is a realistic depiction of the same land surface. The Iberian Peninsula and the Mediterranean are clearly visible at the bottom right; the Nile River (the right hand of the “T”) divides Africa, and the Red Sea separates the Arabian Peninsula from Africa. The Indian Ocean can be seen in the upper right. The whole earth is surrounded by water, reflecting a common assumption in the Middle Ages and Renaissance that the spheres surrounded the earth (see Image 2). |
| Holy Land: Ayer MS map 1, f. 15v-16r (Image 4) |
 Dati’s Map of the Middle East illustrates the illuminator’s effort to intermingle text and image. This terrestrial map is not based on portolan charts — the Mediterranean is represented as a rounded rectangle, and the shoreline is not accurately represented. Although useless for actual travel, this map offered the reader an opportunity to imagine pilgrimage or envision the events of ancient or Biblical history. Most portolan charts represented the inland city of Jerusalem and the Mount of Calvary (sometimes with three crosses on it) although they did not, as a rule, represent inland rivers, lakes, and seas. Dati’s source may have been a Ptolemaic map, which represents rivers and lakes. Ptolemy’s Tabula Asiae IV depicts the same area as Dati’s Middle East including the Caspian Sea and the Indian Ocean, but the graphic conventions are almost entirely unrelated. Dati’s representations of the seas flowing along the Jordan River are schematic; no attempt has been made to represent them as realistic. This may indicate reliance on verbal or written descriptions of the Middle East, rather than visual maps. Dati’s map bears a striking resemblance to Beatus of Liebana’s world map, compiled circa 776. It bears no resemblance to the circular maps of Jerusalem and other mappamundi such as the Hereford map. Interestingly, the Catalan Atlas (Majorca, 1375) represents the Dead Sea and much of the topography in a similar way. |
| Fez: Ayer MS map 1 f. 19r (Image 5) |
 Located at the opening of Book Four, this is the first portolan map in Dati’s Sfera. It represents the extreme western end of the Mediterranean and the first archipelagos in the Atlantic, the Canaries or Fortunate Islands. The illumination of the four islands (in the lower right corner) has been damaged, but one can still discern their rough outline. The three inland cities commonly found on portolan maps are named: Morocco, Fez, and Rabat. The coastline is realistically represented and ends at the Strait of Gibraltar (the Spanish side of the strait appears near the text in the first stanza). Although based on portolan charts, Dati’s maps could not be used for navigation or navigational instruction — they contain no rhumblines, and their fragmenting would have made it impossible to get a sense of how one traveled across the Mediterranean other than along the coastline. |
| Jerusalem: Ayer MS map 1, f. v21 (Image 6) |
 Dati’s map of Jerusalem is a hybrid. It shows its portolan influence along the coastline — the shoreline is accurately rather than schematically represented, including the names of the principal seaports. Inland, though, Dati’s representations are closer to those found on medieval mappamundi — Jerusalem, represented as all cities are on Dati’s maps, as a castle, and to the east of Jerusalem the Dead Sea and the Jordan River are schematically represented as are the Caucasus Mountains with the famous Basilica of St. Katherine. |
List of Images
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| Bibliography
Almagià, Roberto. Monumenta cartographica vaticana. Vatican City, 1944. I: 118-29. Bertolini, Lucia. “L’Attribuzione della “sfera” del Dati nella tradizione manoscritta.” In Studi offerti a Gianfranco Contini dagli allievi pisani. Firenze: Casa Editrice Le Lettere, 1984. pp. 33-43. —. “Censimento dei manoscritti della Sfera del Dati,” Annali della Scuola normale superiore di Pisa: Classe di Lettere e Filosofia, 3rd ser., “Manoscritti della biblioteca Laurenziana,” 12:2 (1982): 666-705; “Manoscritti della Biblioteca Riccardiana,” 15:3 (1985): 889-940; and “I manoscritti della Biblioteca Nazionale Centrale e dell’Archivio di Stato di Firenze,” 18:2 (1988): 417-588. Brucker, Gene, ed. Two Memoirs of Renaissance Florence: The Diaries of Buonaccorso Pitti and Gregorio Dati. Trans. by Julia Martines. New York: Harper & Row, 1967; repr. Prospect Heights, IL: Waveland Press, 1991. Nordenskiöld, Adolf Erik. “Dei disegni marginali negli antichi manoscritti della Sfera del Dati.” Bibliofilia 3 (1901-2), pp. 49-55. Segatto, Filiberto. “Un’immagine quattrocentesca del mondo: la Sfera del Dati.” In Memorie, Accademia nazionale dei Lincei: Classe di scienze morali, storiche e filologische, 8th ser., 27 (1983): 147-81. |