Publication Date
2009
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Scientifically indebted to Hellenistic cosmography, to Eratosthenes and his contemporary Marinus of Tyre in Alexandria in the 2nd century A.D., at the height of the territorial extension of the Roman Empire, Claudius Ptolemy, successor to Eratosthenes at the Library of Alexandria (Egypt) prepared a geographical manual that would allow anyone who was familiar with concepts of astronomical co-ordinates and geometric designs to prepare maps of the known inhabited world.

The Greek tradition of the codices of Ptolemy's Geography is divided into two branches: the first, which historians have dubbed "Group A", comprises eight books, along with twenty-six regional maps and a map of the known inhabited world; the second branch, termed "Group B", had sixty-four regional maps and a map of the oikumene. It is necessary to emphasise that the differences between the two manuscript versions of the Geography in Greek have nothing to do with the text, but rather with the number of maps.

In contrast with Ptolemy's most influential work, the Almagest, known through out the West in the Latin translation of Gerardo da Cremona who translated the text from Arabic in 1172, the Geographiké Uphégesis of Ptolemy written in Alexandria in the 2nd century A.D., known in Arabic as early as the 9th century, remained largely unknown in the West until the beginning of the fifteenth century.

it was only in the early years of the fifteenth century that the Byzantine scholar Manuel Chrysoloras brought to Florence a copy of the Geographiké Uphégesis (Guide to Cartography) by Ptolemy, possibly together with maps. Jacopo Angeli da Scarperia (1360-1410/1411), a pupil of Emanuele Crisolora, translated it into Latin between 1406 and 1409. Jacopo Angeli and the most important Florentine humanists immediately recognised the value of Ptolemy's Geography in the so called "theoretical chapters" that focused on the resolution of such problems as the graphic representation of the oecumene, and theoretically the entire earth, on a flat surface without altering the proportions and forms of the Earth as did previous medieval and Renaissance circular mappaemundi. In chapters 23 and 24 of Book I and in chapter 6 of book VII of the Geography (books II to VII contain a long list of more than 7.000 records of places with their respective latitudes and longitudes which cover all the oecumene, which permit the correct plotting of geographical locations on a map) Ptolemy provided instructions detailing the construction of maps according to three geometrical methods. based on a grid of meridians and parallels.

At the time, Ptolemy placed the ends of the known and inhabited Earth at Thule (placed at 63ºN), the anti-Meroe parallel at 16º25'S, the Fortunate Islands to the West, corresponding to the prime meridian, and Sera Metropolis to the East, at a longitude of 180º. Whatever lay beyond these latitudes and longitudes was a terra incognita for him. The oikumene and this terra incognita occupied 6/7ths of the surface of the globe, effectively relegating the oceans to great 'mediterranean' basins. Due to extreme levels of cold (beyond the Arctic and Antarctic circles) and excessive heat (the equatorial belt), more than half of the Earth's surface was deemed to be uninhabitable.

Geographical peculiarities of Ptolemy's oikumene include a Mediterranean Sea that has been elongated more than 15º in terms of its actual dimensions and an Indian Ocean that is enclosed in a sort of enormous lake in whose centre is to be found the island of Taprobana. Although he refined the knowledge of Marinus of Tyre and even that of Hipparchus, Ptolemy chose to correct the measurements of the maximum circumference of the Earth to 180,000 stadia, as had been determined by Posidonius, moving away from the more precise estimates of 250,000 stadia that had been calculated by Eratosthenes in the 1st century A.D. He thus positioned the greater part of the known inhabited world in the Northern hemisphere and shrank the globe. The importance of Ptolemy's Geography in the Renaissance is demonstrated by the existence of hundreds of manuscripts in Greek, in Latin and vernacular (53 with maps) and 48 printed editions until 1730 of which 38 were printed before 1600 (the editio princeps, without maps, was printed in Vicenza in 1475). The following are, in synthesis, the principal stages of the production and the tradition of the translations of the Geography into Latin and the vernaculars.

• In 1409 Jacopo Angeli da Scarperia translated the Geographiké Uphégesis from Greek to Latin; he also wrote an "Introduction" which explained the value of this work in comparison to Pliny's Historia Naturalis.

• In 1415 Francesco di Lapacino and Domenico da Buoninsegni translated into Latin the toponyms of the maps.

• In 1418 cardinal Guillaume Fillastre wrote the first commentary on the Geography (Guillaume Fillastre, Introductio in Pomponii Melae Cosmographiam Cod. Nancy 441, in Gautier Dalché, P., "L'oeuvre géographique du Cardinal Fillastre († 1428). Représentation du monde et perception de la carte à l'aube des découvertes", AHLDMA, 59, 1992, pp. 357-36).

• Around 1460 Donnus Nicolaus Germanus wrote a new Latin "Dedication" to the Geography (to Paul II and to Duke Borso d'Este) in which he explained both the importance of Ptolemy's second projection and the reasons for adopting it.

• In 1474 Johannes Regiomontanus composed in Nuremberg the Annotationes Joannis De Regio Monte, in errores commissos a Jacobo Angelo in traslatione sua, (published in 1525 by Bilibald Pirkheimer) in which he severely criticised Jaopo Angeli's translation and proposed a new translation of Book I and part of Book VII, the "theoretical chapters."

• In 1478 Domizio Calderini revised Jacopo Angeli's translation for the 1478 Roman edition of the Geography.

• In 1482 Francesco Berlinghieri, after nearly 30 years of work, published a translation of the Geography in Tuscan, "in terza rima".

• In 1514 Johannes Werner published in Nuremberg Regiomontanus' translation together with the "Libellus de quatuor terrarum orbis in plano figurationibus ab eodem Ioanne Vernero novissime compertis & enarratis" which explained how to construct the cordiform projection (in Ptolemaeus, Claudius. Geography. Nuremberg: Stuchs I., 1514, f. 43v. - 48v).

• In 1525 Bilibald Pirkheimer published in Strasbourg a new Latin translation of the Geography.

• In 1548 Pietro Andrea Mattioli published in Venice the first Italian translation of the Geography.

• In 1561 Girolamo Ruscelli published in Venice a new Italian translation of the Geography based upon Münster's Latin version of the text.

• In 1578 Gerard Mercator published the 27 maps of the Geography as a work of historical Geography and cartography.

• In 1598 Antonio Magini (for both the mathematical content and cartography) and Leonardo Cernoti (for the Italian translation) published in Padua the third Italian translation of the Geography.

Traditionally, the recovery of the Geography in the fifteenth century was perceived as the event marking the beginning of a so-called 'Ptolemaic Revolution', with the implication that the 'uncritical' and religiously inspired cartography of the Middle Ages was replaced by the scientific cartography of the Renaissance. Recent scholarship has refined this over-simplified representation of the impact of the Geography and has shown that the reception of Ptolemy's work was a much more complex process than the traditional literature allows for. Instead, it is now suggested that different modes of reception should be distinguished.

A first realm of the Geography's reception to consider is that of the humanists. Humanists were mainly interested in Ptolemy's geographical work primarily because it was a hitherto unknown classical text. They apparently did not prefer Ptolemy to other authors of classical geography, such as Pliny the Elder, Strabo and Pomponius Mela, all of whose geographical works are of a descriptive rather than a mathematical character.

A second realm of the reception of the Geography to consider is that of map-making. Ptolemy's cartography was not, however, the complete novelty in the Latin West as the older scholarly literature suggests. The recovery of Ptolemy's cartography in the Latin West at the start of the fifteenth century should be seen as a new stimulus to existing knowledge, not a revolutionary factor. Some medieval grid-based maps survive, although it is true that the function of the grid differs fundamentally from Ptolemy's latitude and longitude. In the thirteenth century, Roger Bacon had already described a mathematical projection system for a world map. And a number of tables were in wide circulation from the twelfth century onwards, giving the degrees of latitude, and often longitude, for important western European places.

A third aspect of Ptolemy's reception to consider is the way the Geography was understood within the framework of traditional geographical knowledge and the the long process of the European expansion.

Bibliography
Ptolemy's Almagest; translated and annotated by G. J. Toomer, London, Duckworth, 1984. DILKE, O. A. W., "The Culmination of Greek Cartography in Ptolemy (with additional material supplied by the editors)," in The History of Cartography, eds. J. B. Harley - D. Woodward, vol. 1, Cartography in Prehistoric, Ancient and Medieval Europe and the Mediterranean, Chicago, University of Chicago Press, 1987, pp. 177-200. GENTILE, S., Firenze e la scoperta dell'America. Umanesimo e geografia nel '400 fiorentino, Firenze, Olschki, 1992. J.L. Berggren - A. Jones (eds.), Ptolemy's Geography. An Annotated Translation of the Theoretical Chapters, Princeton, Princeton University Press, 2000. GENTILE, S., "Umanesimo e cartografia: Tolomeo nel secolo XV," in La cartografia europea tra primo Rinascimento e fine dell'Illuminismo, di D. R. Curto, A. Cattaneo, A. F. Almeida, Firenze, Olschki, 2003, pp. 4-18. DALCHÉ, P. Gautier, "The Reception of Ptolemy's Geography. (End of the Fourteenth to Beginning of the Sixteenth Century)", in Cartography in the European Renaissance, edited by David Woodward, vol. 3 della History of Cartography, Chicago, University of Chicago Press, 2008, pp. 285-364.