centre informatique – Les Globes de Mercator de l'UNIL http://wp.unil.ch/mercator/en/ Le récit d'une découverte à l'Université de Lausanne Fri, 23 Nov 2018 12:42:25 +0000 en-US hourly 1 https://wordpress.org/?v=5.5.1 Insets http://wp.unil.ch/mercator/en/celestial-insets/ Mon, 29 May 2017 12:17:19 +0000 http://wp.unil.ch/mercator/les-cartouches-celestes/ [...]]]> The celestial globe has two insets, one a dedication and the other an intellectual property notice, along with an inscription of the place and date of publication.
DedicationIntellectual property noticePublication
The first inset contains a dedication to the Bishop of Liège under his coat of arms.

George of Austria (1505-1557), like Nicolas Perrenot on the terrestrial globe, was a great figure of his time. A natural son of Emperor Maximilian I, he began his ecclesiastical career in 1525 as Bishop of Brixen. In 1541 he was appointed Prince-Bishop of Liège by Emperor Charles V, who wanted a devoted clergyman in this strategic position.

Ampliss[imo] Praesuli Principiq[ue] ill[ustrissi]mo Georgio ab Austria Dei dispositione Episcopo Leodiensi, Duci Bullonensi, Marchioni Fracimotensi, Comiti Lossensi, etc, mecoenati optime merito dd. Gerardus Mercator Rupelmondanus.

Ampliss[imo] Praesuli Principiq[ue] ill[ustrissi]mo Georgio ab Austria Dei dispositione Episcopo Leodiensi, Duci Bullonensi, Marchioni Fracimotensi, Comiti Lossensi, etc, mecoenati optime merito dd. Gerardus Mercator Rupelmondanus.
To the greatest patron and very famous Prince George of Austria, Bishop of Liège by the grace of God, Duke of Bouillon, Marquis of Franchimont, Count of Looz, etc. and the most deserving of benefactors, Gerardus Mercator of Rupelmonde gives and dedicates this globe.
The second inset serves as a framework for the globe’s intellectual protection, stipulating that Mercator secured a ten-year ban on its imitation and sale.

Inhibitum est ne quis hoc opus imitetur, aut alibi factum vendat, intra fines Imperii, vel prouinciarum inferiorum Caes. M[aiesta]tis ante decennium, sub poenis et mulctis in diplomatibus cotentis. Obernburger & Soete subscrib[unt]

Inhibitum est ne quis hoc opus imitetur, aut alibi factum vendat, intra fines Imperii, vel prouinciarum inferiorum Caes. M[aiesta]tis ante decennium, sub poenis et mulctis in diplomatibus cotentis. Obernburger & Soete subscrib[unt]
It is prohibited for any person to imitate this work or to sell one made elsewhere, within the boundaries of the Empire or the United Provinces of His Imperial Majesty, for one decade, subject to the penalties and fines established by official documents. Signed Obernburger and Soete
Mercator also took care to indicate the place and date of the globe’s publication, an inscription that can be found under the tail of Pisces Austrinus, itself under the constellation of Capricorn.

Louanij anno Domini 1551 mense Aprili

Louanij anno Domini 1551 mense Aprili.
At Leuven in the year of our Lord 1551, in the month of April.
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Constellations http://wp.unil.ch/mercator/en/constellations/ Mon, 29 May 2017 12:16:18 +0000 http://wp.unil.ch/mercator/les-constellations/ [...]]]>
Was it merely a desire to make the night-time world familiar that people filled the sky with mythological figures and assorted animals? Certainly not. The starry vault of heaven was an indispensable addition to the spherical geometry of the Earth itself, making it possible to identify the fundamental circles of the celestial globe in the night sky. It provided the spherical universe with a practical application.Germaine Aujac

In his representation of the constellations and their nomenclature, Gerardus Mercator produced the most comprehensive celestial globe of the 16th century. These representations included figures from literary tradition inspired by Greek sources. In this respect, the German-Flemish cartographer sometimes seems less of an astronomer than a man of the Renaissance who selected his sources with a critical eye.

Each constellation is indicated with its Latin and Greek names, with an added transliteration of its Arab name (or what was meant to be Arabic in the 16th century). Mercator must have consulted several sources for his nomenclature and, on the face of it, proceeded in encyclopaedic fashion. His knowledge of astronomy came from books, not from observations.

Mercator’s Pleiades

Modern representation of the Pleiades. Source : stellarmap.com

Pleiades

The Pleiades cluster has been known since Antiquity. Some of its stars can be seen with the naked eye. Only four of them are described in Ptolemy’s star catalogue and its offshoots. The Mercator’s globe presents seven stars.

Portfolio of constellations
Mercator took great care to make his globes useful. While the pamphlets that originally accompanied them have been lost, the cartographer discusses the numerous applications of his celestial globe in a copy of Declaratio insigniorum utilitatum found in Milan. By explaining certain ways of handling his celestial globe, he tells his contemporaries that it can be used :
  • to find out the “quantity of day”, i.e. the latitude and times at which the Sun rises and sets ;
  • to recognise the stars in the sky, even without the least prior knowledge ;
  • to provide the wherewithal to measure how high a star or the Sun stands above the horizon and the Sun’s distance below the horizon ;
  • to indicate the time it takes for a star to complete its course above the horizon, from the time it rises to the time it sets ;
  • to determine the meridian of a place ;
  • to find the latitude of a country ;
  • to situate the sign and degree of the Zodiac where the Sun is located ;
  • to determine the time of year when a star will pass the meridian at midnight ;
  • to determine the time when a star will reach the meridian ;
  • to determine when twilight will fall.
Find out more
  • Union Astronomique Internationale / International Astronomical Union
  • Aujac, G. (1976) « Le ciel des fixes et ses représentations en Grèce ancienne », in : Revue d’histoire des sciences, Vol. 29, N° 4, pp. 289-307 [URL].
  • Dekker, E., Krogt, P. van der (1994) « Les globes », in : Watelet, M. (1994), pp. 242-267.
    Dekker, E. (2013) Illustrating the phaenomena : celestial cartography in Antiquity and the Middle Ages, Oxford : Oxford University Press.
  • Whitfield, P. (1995) The Mapping of the Heavens, London : The British Library.
  • Woodward, D. (2007a) Cartography in the European Renaissance, « The history of cartography » (J.B. Harley & D. Woodward, eds.), Vol. 3, Chicago : The University of Chicago Press, Parties I-3, I-4, I-5, pp. 53-173.
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Celestial sphere http://wp.unil.ch/mercator/en/celestial-sphere/ Mon, 29 May 2017 12:15:52 +0000 http://wp.unil.ch/mercator/la-sphere-celeste/ [...]]]>
In the fabric of space and in the nature of matter, as in a great work of art, there is, written small, the artist’s signature.Carl Sagan

Mercator’s celestial globe is surrounded by a brass meridian capped at the North Pole by a time dial (absent on the Lausanne copy) and a horizon ring indicating the main religious holidays and their dates along with the twelve signs of the Zodiac for astrological forecasts.

The sphere is covered with twelve gores extending to the 70th parallels, with each polar region capped by a round calotte. The celestial gores are aligned with their equatorial coordinates rather than the coordinates of their ecliptic. They meet at the celestial poles, which thus coincide with the axis of the globe’s base.

A large part of the area around the South Pole is blank, which is no surprise since it could not be seen from the latitudes of Europe. Thus, stars with a declination exceeding an absolute value of 66°30’ are missing. The constellations are named in Latin and Greek with an Arabic transliteration

Mercator’s globe shows a precession correction of 20°55’, in line with the theory of Nicolaus Copernicus. The equator and ecliptic are graduated with the degrees numbered on them by tens. The prime meridian runs just next to the tail of Pisces, shown below the wing of Pegasus.

The horizon ring, or rational horizon, is divided width-wise into two halves :

  • the inner half, from inside to outside, indicates the ring’s division into degrees, the signs of the Zodiac, the days and months of the Roman calendar, the main religious holidays and the main winds in the different seasons ;
  • the outer half indicates astrological forecasts, a trace of Arab astrology which still had its followers in the 16th century. Historians suppose that in including them Mercator must have made a concession to popular beliefs.
Reproduction des fuseaux du globe céleste : horizon et calottes

© Royal Library of Belgium, reproduced with permission

The relative shapes and dimensions of individual stars are shown in six different sizes along with the nebulae. A list of models is given near the top of the globe, above the constellation Gemini.

Magnitudines stellarum (size of the stars). © UNIL Magnitudines stellarum (size of the stars). © Royal Library of Belgium, reproduced with permission

Apart from the Milky Way and a large number of stars not belonging to symbolic asterisms, Mercator included nearly all of Ptolemy’s 1022 stars (according to J. van Raemdonck there are 934) spread across 51 constellations, compared with the 48 constellations commonly referred to since Antiquity. Among the additional representations we can find :

  • Antinous, made up of twelve stars, situated in the southern hemisphere below the feet of Orion ;
  • Lepus, made up of twelve stars, situated in the southern hemisphere below the feet of Orion ;
  • Cincinnus (Caesaries, Berenicis crinis, Trica), made up of one star and two nebulae and located in the northern hemisphere under the tail of Ursa Major (the Plough). Coma Bernecis (Berenice’s Hair) has been on the official list of constellations since 1930 ;
  • Canicula (Almogelsa, Alschere, Procyon) is situated in the northern hemisphere below the tail of Cancer, its correct position, contrary to the location in the southern hemisphere assigned to it later by Jocodus Hondius.
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Representation of the constellations http://wp.unil.ch/mercator/en/representation-of-the-constellations/ Sat, 29 Apr 2017 08:36:28 +0000 http://wp.unil.ch/mercator/representation-des-constellations/ [...]]]> The features of celestial globes reveal the aspirations of their builders, who either decide to follow conventional iconographic representations of the constellations or to create new ones instead.

Mercator distanced himself in a number of ways from his master Gemma Frisius. For experts such as Elly Dekker (1994), he apparently tried to reconcile the opinions of Claudius Ptolemy and Nicolaus Copernicus.

For example, in the 16th century, the constellation Lyra was traditionally shown as a bird or as a combination of a bird and a sort of violin. These representations stem from the Arab influence in the circulation of Ptolemy’s Almageste. Seeking greater accuracy, Mercator replaced the bird-violin image with a Vultur cadens, a musical instrument of Greek origin that was unknown in the Arab world. The Greek version of the Almageste actually described Lyra as being composed of a “shell” (i.e. a tortoise shell, like the one used by Hermes to make the very first lyre) with horns and a crossbar.

A number of human figures are dressed on Mercator’s globe whereas Frisius shows them naked.

Mercator’s cartographic aspirations can also be seen in the sizeable nomenclature of individual constellations and stars. The constellations are identified by their Latin and Greek names with a transliteration in Arabic (or what is meant to be Arabic). Such efforts point up Mercator’s erudition. From this point of view his celestial globe is the most comprehensive of any made in the 16th century. Here are a few of Mercator’s additions :

  • Ceginus (Gamma Bootis, Phi Bootis),
  • Incalurus (Mu Bootis),
  • Saclateni (Êta Aurigae),
  • Angetenar (Tau Eridani),
  • Acarmar (Thêta Eridani),
  • Alphart (Alpha Hydrae),
  • Markeb (Kappa Puppis, Kappa Velorum)
  • etc.
Find out more
  • Constellations : in his representation and of the constellations and his nomenclature, Mercator produced the most comprehensive celestial globe of the 16th century.
  • Dekker, E., Krogt, P. van der (1994) pp. 260-263.
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Precession of the equinoxes http://wp.unil.ch/mercator/en/precession-of-the-equinoxes/ Sat, 29 Apr 2017 08:18:38 +0000 http://wp.unil.ch/mercator/precession/ [...]]]>

The influence of Nicolas Copernicus can be seen in the precession of the equinoxes, i.e. the gradual change in the Earth’s rotational axis. Mercator applied the new Copernican view to calculate stars’ positions, which in this theory referred to the year 1550.

Calculating to correct for precession was the biggest astronomical challenge faced by users of Ptolemaic star positions. A catalogue that defines stars’ coordinates based on a slowly changing system of reference always indicates the positions for a given moment in time, called the epoch. To calculate a star’s position at a later epoch based on existing catalogues, astronomers had to increase the star’s ecliptic longitude by a constant value as determined using the well-known theory of precession.

In the 16th century, a number of theories of precession coexisted. The values that were used to correct for precession, i.e. by increasing the longitude in relation to the one at the time of Ptolemy, could vary enormously.

In this area Mercator once again distanced himself from his master Gemma Frisius. Comparing the two geographers’ globes, we can for instance see a difference in the longitude of the star Regulus. The precession correction of Frisius’ globe (1537) is 19°40’, whereas the one on Mercator’s globe (1551) is 20°55’. By modern standards, a difference of 1°15’ would mean a difference of epoch corresponding to almost 90 years. This contrasts with the 14 years which actually separated the two globes’ publication. It is worth noting that celestial globe designers always opt for an epoch close the date their creations go into production.

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Star positions http://wp.unil.ch/mercator/en/star-positions/ Sat, 29 Apr 2017 08:18:05 +0000 http://wp.unil.ch/mercator/positions-stellaires/ [...]]]> Star catalogues in the 16th century were all inspired by Ptolemy and contained discrepancies. These were due to mistakes made by printers when copying and republishing the catalogues, resulting in differences in the stars’ given positions.

There are variations between the globe published by Gemma Frisius (1537) and the one published by Mercator (1551), for example in the representation of Aires and Gemini. This suggests that Mercator drew on different sources to indicate stars’ positions. Since his globe was published later, he no doubt believed that these positions were more appropriate.

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Astronomical coordinates http://wp.unil.ch/mercator/en/astronomical-coordinates/ Sat, 29 Apr 2017 08:17:40 +0000 http://wp.unil.ch/mercator/coordonnees-astronomiques/ [...]]]>

For centuries the positions of stars were taken from the star catalogue in Claudius Ptolemy‘s Almageste and it was not until the late 1500s that the new observations of Tycho Brahe would be more accurate.

In the 16th century men of science like Gemma Frisius and his pupil, Gerardus Mercator, referred to star catalogues that all had one thing in common : the stars’ positions were described using a system of coordinates whose fundamental plane was the elliptic. On a celestial globe like the one produced by Frisius in 1537, the meridians were generally drawn from the north elliptic pole to the south elliptic pole and not, as in the case of Mercator’s terrestrial globe, from the north equatorial pole to the south equatorial pole.

Mercator’s celestial globe is one of the few examples that differs from the usage of its day by using a system of equatorial coordinates that sets the German-Flemish globemaker apart from other contemporaries. This was no small feat as Mercator applied his system to over a thousand stars. Experts suppose he had an effective method for converting the coordinates, suggesting that he used a universal astrolabe.

Diagram of equatorial coordinates
In this system, the Earth is at the centre. Projected onto the celestial sphere, the Earth’s equator becomes the celestial equator (blue circle). The same holds for the Earth’s north and south poles. The elliptic (yellow circle) is the plane of the Earth’s orbit around the Sun. The hour circle, or meridian of the given star, is the large circle passing through the poles and the star itself. The intersection of the elliptic and the celestial equator sets two points. The one pointing to the constellation Pisces is called the vernal point, from which the right ascension (horizontal red line) leads along the celestial equator. The declination is determined by the position of the star on the meridian (vertical red line).
© Autiwa, source : Wikipedia.
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Influences and sources http://wp.unil.ch/mercator/en/influences-and-celestial-sources/ Sun, 23 Apr 2017 12:54:15 +0000 http://wp.unil.ch/mercator/influences-et-sources-celestes/ [...]]]>
Star positions, precession, the style of constellations and the nomenclature used for the stars and their figures are the features that make it possible for globemakers to distinguish themselves. […] Comparing the celestial globe by Gemma Frisius with the one by Gerardus Mercator proves that Mercator used sources that were very different and more recent than those of Frisius.Elly Dekker

Past historians, influenced by Fiorini (1899) and Stevenson (1921), contended that Mercator did not have the same talent in astronomy as he did in geography, even though his celestial globe could still be considered a remarkable scientific work. Yet more recent studies, especially by Elly Dekker, have shown that Mercator’s celestial globe presented considerable improvements compared with earlier spheres, in particular the one designed by Gemma Frisius.

The astrological information on Mercator’s celestial globe stemmed from sources that were translated during his time. For example, he used De supplemento, an almanac by Girolamo Cardano first published in Milan in 1538 and reprinted in Nuremberg in 1543.

Mercator also knew Tetrabiblos by Claudius Ptolemy, a four-volume mathematical study translated and published in Nuremberg in 1535 by Joachim Camerarius. Like all his contemporaries Mercator also practised astrology, which he promoted by producing his celestial globe.

Besides the up-to-date information that Mercator presented on the nature of the stars, their positions were set in accordance with the brand-new theory of the precession of the equinoxes published by Nicolas Copernicus in 1543 in his De revolutionibus orbium coelestium, a book which laid the bases of heliocentrism. Mercator was thus the first globemaker to tap into this theory.

Find out more
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Insets http://wp.unil.ch/mercator/en/terrestrial-insets/ Fri, 21 Apr 2017 13:23:33 +0000 http://wp.unil.ch/mercator/cartouches-terrestres/ [...]]]> The terrestrial globe has seven text insets. Most are actually captions, a bit longer than usual, dealing with geographic features. Two others provide information on the globe’s design.
SignatureDedicationScaleEuropean citiesCaptions
First there is the inset in which Mercator signed the globe as his creation and indicated the year it was made (or rather the year the copper printing plates were made).

Edebat Gerardus Mercator Rupelmundanus cum privilegio Ces. Maiestatis ad an. sex Louanii an. 1541

Then there is an inset dedicating the work to the Lord of Granvelle, Nicolas Perrenot.

Perrenot was an important figure in his time. He was chancellor in the court of Charles V and even a close adviser to the emperor. By 1541 he had held the position of guardian of the seals for nine years. On the globe, above Mercator’s dedication, are the Lord of Granvelle’s coat of arms and the words Sic visum superis (“Thus you will see the world from above”).

Illustriss[imo] D[omi]no Nicolao Perrenoto Domino a Granvella Sac[rae] Caesareae Ma[iesta]ti a consiliis primo dedicatu[m]

A third inset can be compared to the scale indicated on present-day maps. Given the wide range of units of measure used in his time, Mercator provided a key for converting some of them.

Si quorum voles locoru[m] distantia[m] cognoscere lector, circinu[m] eoru[m]de[m] distantiae adaptatu[m] in aequatore[m] transferto hic tibi q[ua]libet particula i[n]tercepta mille aria referet Hyp:18, Gal:20, Germ:15, Milia pas:60, Stadia:500

If you, reader, wish to know the distance to certain places, measure it as adjusted by the compass placed on the equator; the distance will be 18 Spanish miles, 20 French miles, 15 German miles, 60,000 podes, 500 stadia.
Given the density of place names in Europe, Mercator had to list certain cities in a separate inset, replacing them with a mere number on the globe.

Europae aliquot insigniorum civitatum nomina, quae suis inferi locis angustia operis prohibuit

Here are the names of a few famous cities in Europe that lack of space prevented Mercator from indicating below their position.

Albionis (England)
1 Saltzburgum (Salisbury)
2 Bristou (Bristol)
3 Vestchester
4 Chester (Chester)
5 Jorc (York)

Scotiae (Scotland)
6 Edinburgum regia (Edinburgh)
7 Catnes

Hyberniae (Ireland)
1 Unflor
2 Solli
3 Dondal (Dundalk)
4 Dubelyn (Dublin)
5 Wacfort (Wateford)
6 Lamerich (Limerick)
7 Galuei (Galway)

Hispaniae (Spain)
1 Bermeo (Bermeo)
2 Soria olim Numantia (Soria formerly Numance)
3 Burgus (Burgos)
4 Compostella (Compostelle)
5 Marbella (Marbella)
6 Bera
7 Carthago nova (Cartagena)
8 Valentia (Valencia)
9 Tarracon (Tarragona)
10 Barsalona (Barcelona)

Galliae (Gaule)
1 Monspessulanus (Montpellier)
2 Tullium (Toul)
3 Roari (Rouen)
4 Verodunum (Verdun)
5 Sedunum (Sion)
6 Basilea (Basel)
7 Colonia Agrippina (Cologne)
8 Gandanum (Ghent)
9 Amsterodamum (Amsterdam)

Germaniae (Germany)
1 Marcheburgum olim Amasia
3 Francofordia (Frankfurt)
4 Augusta Vindelicorum (Augsburg)
6 Norenberga (Nuremberg)
7 Praga (Prague)
8 Erfordia (Erfurt)
9 Brunsuiga (Brunswick)
10 Hamburgum (Hambourg)
11 Copenhaga metropolis Daniae (Copenhagen capital of the Danes)
12 Arhusen (Aarhus)
13 Schlesibyc (Schelswig)
14 Lubecum (Lübeck)
15 Stetin (Szczecin)
16 Brandenburgum (Brandebourg)
Italiae (Italy)
1 Patavium (Padova)
2 Aquilegia (Aquila)
3 Florentia (Florence)
4 Perusium (Perugia)
5 Sessa
6 Policastro (Policastro Bussentino)
7 Brundusium (Brindisi)
8 Adria

Greciae (Greece)
1 Messena (Messina)
2 Corinthus (Corinth)
3 Athenae (Athens)
4 Ambracia nunc Narta (Ambracie now Nartë)
5 Thessalonica (Thessaloniki)
6 Philippipolis
7 Adrianopolis (Edirne)

Finally, three insets contain more detailed captions: one in Europe, one in Asia and and one near Antarctica.

Albion & Hybernia insulae communi nomine Britannicae vocantur

The islands of Albion and Hybernia, commonly referred to as the British Isles.

Mangi nobilissima provincia 9 habet in se regna & 1200 civitates, evicta est a Tartaroru[m] Imp[eratore] Cublai anno 1268. Inter Mangi aute[m] et Zipangri insulam 7448 numeratas ait a nautis insulas M. Paul. Venetus lib. 3. cap. 8.

Mangi, the noblest of the provinces containing nine kingdoms and 1200 towns and cities, was defeated by the Emperor of the Tartars, Kublai, in 1268. Paulus Venetus says in book 3 chapter 8 that between Mangi and the island of Cipango the sailors counted 7448 islands.

Insulas hic uspiam esse testatur M. Paul. Venetus in quibus certo anni tempore ruc avis apparet tam vastae magnitudinis ut elephantem in sublime attollat

Paulus Venetus states that there are islands somewhere in this area. At certain times of the year one can observe the rokh, a bird so large that by accounts it can lift an elephant into the air.

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Bestiary http://wp.unil.ch/mercator/en/bestiary/ Thu, 20 Apr 2017 09:56:36 +0000 http://wp.unil.ch/mercator/bestiaire/ [...]]]>
For us the picturesque figures rising out of the water could be illustrations from children’s books […]. At the time there was a persistent belief in the existence of griffons, unicorns, dragons, the phoenix, monstrous races […]. Modern science was in its infancy […] and, in those days, the medieval imagination was still free to shape its own view of the natural world.Joseph Nigg

There seem to be a number of complementary reasons behind illustrations of sea monsters or other exotic creatures in the field of cartography. For mapmakers the idea was:

  • to liven up the image of the world with decorative features,
  • to fill empty spaces with information,
  • to draw attention to the vitality of the oceans and the variety of creatures living in them,
  • to suggest that the oceans and uncharted lands could be sources of danger,
  • to serve as the graphic memory of literature on the subject,
  • to provide points of reference in a geography of the marvellous,
  • to draw attention to the artistic talent of the cartographer, who could then sell his work at a higher price, depending on the quality and quantity of the illustrations.
Sea and land creatures

For historians, three representations of sea monsters are predominant in Renaissance cartography: Olaus Magnus‘s Carta Marina (1539); the Monstra Marina & Terrestria map (1544) by Sebastian Münster, partly inspired by Olaus Magnus; and the Islandia map by Abraham Ortelius, published in Theatrum Orbis Terrarum (1586) and inspired by the two previous works.

Gerardus Mercator was particularly influenced by Magnus’ Carta marina, which contained the largest, most varied and most comprehensive collection of sea monsters of the day.

Mercator’s terrestrial globe is illustrated with eleven sea monsters, seven of which were taken from Magnus’s Carta marina and two others from Gonzalo Fernandez de Oviedo‘s Historia general de las Indias (1535), a book that represented the very first images of animals in America. Mercator no doubt used both Magnus and Oviedo to demonstrate his ability to combine the most recent sources in a nutshell. In addition to the sea monsters he included one terrestrial animal.

The monsters in cartography provides a detailed roundup of Mercator’s sources and inspirations for the twelve sea monsters and opossum.

Find out more
  • Monsters in cartography : a detailed roundup of Mercator’s sources and inspirations for the twelve sea monsters and opossum.
  • Carta marina : by Olaus Magnus, digitised document, World Digital Library: National Library of Sweden.
  • Cosmographey, das ist Beschreibung aller Länder : by Sebastian Münster, German edition 1598, digitised document, Gallica: National Library of France.
  • Theatrum Orbis Terrarum : by Abraham Ortelius, digitised document of the 1570 edition, Library of Congress.
  • Duzer, van C. (2014) Sea Monsters on Medieval and Renaissance Maps, London : The British Library.
  • Nigg, Joseph (2013) Sea Monsters. A voyage around the world’s most beguiling Map, Chicago & London : The University of Chicago Press.

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