More on Spica

Continuing from the last post on star and constellation names, in addition to the use of Spica at an ancient epoch in connection with a determining latitude, it has also been suggested earlier that the prime meridian was associated with the star.



Assyrian period image from Nineveh of Ishtar (Robert Brown 1886:459) holding up a fleur-de-lys or ear of grain, a prototype of the symbolism for the constellation Virgo and its brightest star Spica ('spike' of grain).


According to certain Indian and Muslim (al-Balkhi) schools of astronomy, the eastern city of Yamakoti marked the prime meridian.

Yamakoti, Lanka or Ujjain, Romakapura and Siddhapura were placed in order from East to West at quadrants from each other by Indian astronomers supposedly forming a circle around the earth, with Siddhapura in the Western Hemisphere. However, it is clear that these four points instead only delineate the known world, or about half the globe at the time, as the Muslim writer Al-Biruni notes:

How the Hindus came to suppose the existence of Siddhapura I do not know, for they believe, like ourselves, that behind the inhabited half-circle there is nothing but unnavigable seas.

Earlier in this blog, we noted that Romakapura ('Romaka City') was associated with the astronomy of Ptolemy and other Alexandrian astronomers and therefore Romaka is likely Alexandria rather than Rome (as suggested by some scholars). The city of Ujjain, famed for its astronomical observatory, was located at about 75.5° East longitude in India. Therefore, Romakapura and Ujjain were located about 45 degrees or three hours from each other.

Now, Siddhapura, the city of the Siddhas, or perfected ones, appears related to the Fortunate Isles of Ptolemy, used by the latter as the prime meridian. The Fortunate Isles were the blessed islands, the paradise of the heroes in Western mythology. It seems here that the Siddhas would correspond in Indian terms to the Greek Heros. Now, Ptolemy's Fortunate Isles are generally associated with the area around the Canary Islands or roughly around 15° West longitude and thus about three hours West of Alexandria.

Yamakoti, a city famed for its gold, is easily linked with Suvarnadvipa, the "Gold Island" and would be placed then for consistency three hours to the East of Ujjain. Here is a map of our suggested locations for these Indian meridians.




Click on image for full-size view


Ptolemy's map of the world was derived from that of Marinus, a geographer who lived at the port city of Tyre in Lebanon. Marinus claimed to have gleaned his information from travelers like Diogenes, an Indian who ventured to Rhapta on the African coast, and Alexander, a Macedonian who obtained information on the sea voyage from the the Golden Chersonese (Malaya Peninsula) to Cattigara, the furthest port to the East in Greek geography.

Cattigara was said to be a great emporium of the Sinae. While it is tempting to connect the Sinae with the placename "Chin" and similar latter cognates for China, Marinus and Ptolemy use the terms Thinae and Seres to describe most of what constituted China at the time. As the countries of the Sinae were said to cover the area along the sea (Gulf of Sinae) southeast of India extra Gangem, it would describe the extreme southeast of modern Southeast Asia.

The emporium was placed by Marinus as a few days sailing to the southeast of Zaba, although Ptolemy thinks it was many days from Zaba. The latter market city is normally linked with the kingdom of Champa, although some think it may have been on the east coast of the Malaya Peninsula. Historically though, Champa may have been founded later than Marinus time in the early part of the 2nd century, but the datings here are murky. The country of Linyi, the Chinese name for the latter kingdom of Champa, arises in about 192 CE, but there are indications of earlier antecedents south of the Chinese sphere of influence.


Marinus' Grid System and the Chinese

Marinus of Tyre was the first person in the West to use a grid system marking latitudes and longitudes. However, he was preceded in China where geographers had used such a system since the Qin Dynasty, with particular developments during the Han Dynasty.

Joseph Needham notes that while the grid system in the West was an interrupted development, it continued to be used by the Chinese throughout their history into modern times.

One of Marinus most important informants was a Syrian known as Maes Titianus, who was said to have conducted trade in silk with the Seres (Chinese). It appears that Marinus may have learned about the Chinese grid system from Maes Titianus or possibly from Alexander the Macedonian.

Zou Yan (250 BCE) divided the earth into nine continents through which the Sun passed on its daily rotation. A massive district known as the Red District with China located in the southeast corner appears to describe something similar to the inhabited world of Marinus and that of the ancient Indian astronomers. This district is described as 28,000 li from East to West and 26,000 li from North to South. During this period it is thought that the li represented about a third of a mile, so the dimensions would be about 9,333 miles by 8,666 miles. Zou Yan, though, somewhat like the Hindu astronomers in relation to the mythical circular continents around Meru, apparently inflates the size of the rest of the world in order to conform to traditional cosmology.

The Red District was divided into a three by three "magic square," of nine squares, with each of these nine squares again divided into into another magic square of nine squares. So that from East to West, the district was divided into nine divisions or hours.

Of course, if we accept my identification of Yamakoti and the other three Indian astronomical cities, the total distance between them is in fact nine hours consisting of 135 degrees.

Marinus, however, made the distance from the Fortunate Isles to Cattigara into 15 hours of 225 degrees, while Ptolemy suggested instead 12 hours of 180 degrees. It should be noted that the remaining "uninhabited" area of the world according to Marinus estimate was in fact nine hours of 135 degrees, so maybe there was some miscommunication along the way.

Now getting to the connection of geography with the star Spica, the Huananzi (2nd century BCE) divides the sky into nine fields. For the Daoists, the nine divisions of Heaven corresponded to the nine divisions of Earth. Zou Yan describes the Sun traveling across the nine continents in a day just as it transversed the ecliptic through the year.

The first field of Heaven is led by the asterism Kio, containing the star Spica. The first part of the world, the beginning of the East in Chinese thought, is the region of the Fusang Tree.

The Sun rises in Yanggu (Bright Valley),
Bathes in the Xian Pool,
And rests in the Fusang Tree.
This is called the Dawn Light.
Ascending the Fusang, it commences its journey...
...the Sun travels over the nine continents, and seven resting places.

-- Huananzi: "The Treatise on the Patterns of Heaven"

So, it would appear that Fusang, the beginning of the East for the Chinese, was the limit of the East, or Cattigara, of the Greeks. For certain Indian and Muslim schools of astronomy, Yamakoti also served as the starting point.

Marinus estimated the distance between the Fortunate Isles and Cattigara at 11,250 miles while Ptolemy gave the distance as 9,000 miles as both thought the degree equaled 50 miles at the equator. Again Zou Yan's estimate is about 9,333 miles depending on the exact equation of the li, while the actual distance using our identification of these locations is 8,100 miles.

Ptolemy locates Cattigara at 177° East and 8° 25' South, but his coordinates in this region are overextended in both the eastern and southern directions. Later, during medieval times and the early part of the Renaissance, European maps followed this tradition placing mainland Southeast Asia south of the equator and the coast of China near or beyond 180° East longitude.

When Magellan neared the islands of what is now known as the Philippines he was steering for Cattigara according to shipmate Pigafetta, apparently recognizing Ptolemy's errors in longitude and latitude.

In conclusion, the star Spica was placed at the beginning of the nine fields of Heaven just as the Fusang region was at the head of the nine continents, in the font of the East. The star served to mark the start of the year when the Zenith Moon passed nearest during the year, with the zenith located directly over Tanggu (Yanggu) and the Fusang Tree. This latter location has basically the same identity, at least geographically, with Yamakoti and Cattigara. Marinus of Tyre may have heard of the Chinese grid system together with its starting point from Maes Titianus or Alexander the Macedonian, and simply reversed the order of reference. The Indian astronomers may have heard of the system from Sakadvipa migrants, who had established themselves in India during the country's golden age of astronomy.

Regards,
Paul Kekai Manansala
Sacramento

References

Lewis, Mark Edward. The construction of space in early China, Albany , NY : State University of New York Press, 2006.

Sachau, Edward C. Alberuni's India: An Account of the Religion, Philosophy, Literature, Geography, Chronology, Astronomy, Customs, Laws and Astrology of India About A.D. 1030, Routledge, 2001.

William, Vincent. The Commerce and Navigation of the Ancients in the Indian Ocean, New Delhi, AES (reprint), 1998.

Marco Polo (Glossary)

Marco Polo is important for the purpose of this work because his voyages may have resulted in the transfer of mariner's charts and/or related information that helped give rise to the portolan from the East to Europe. At the least, he mentions the use of mariner's charts by navigators in the Indian Ocean during his voyages.

In describing the island of Sri Lanka (Ceylon/Seilan), Polo says:

It has a circumference of some 2400 miles. And I assure you that it used to be bigger than this. For it was once as much as 3500 miles, as appears in the mariners' charts of this sea.

Again in relating the number of islands in the Indian Ocean, he states:

It is a fact that in this Sea of India there are 12,700 Islands inhabited and uninhabited, according to the charts and documents of experienced mariners who navigate the Indian Sea.

When Polo describes the eastern portion of the East Indies apparently including the Philippines, the Moluccas, etc. he says about the name of the China Sea:

You must know the Sea in which lie the Islands of those parts is called the Sea of Chin, which is as much as to say "The Sea over against Manzi." For, in the language of those Isles, when they say Chin, 'tis Manzi they mean. And I tell you with regard to that Eastern Sea of Chin, according to what is said by the experienced pilots and mariners of those parts, there be 7459 Islands in the waters frequented by the said mariners; and that is how they know the fact, for their whole life is spent in navigating that sea.

Probably Polo got his Chin from Tsina or Tchina in the 'language of those Isles," opposite Manzi, or South China, from which we derive the current name "China."

The history of this name has ancient roots. Ancient Sanskrit literature including the Mahabharata mentions Cina and Maha-Cina. The Nestorian synod of 410 tells of a "Metropolitan of the Islands, Seas and the Interior of Dabag, Chin and Machin."

Dabag is the same as the latter "Zabag," while Chin and Machin are certainly copies of the Indian Cina and Mahacina. Among the Nestorians, Chin or Sin means "China" while Machin/Masin refers to Southeast Asia.

Cina is China among the Indians, while Mahachina appears to refer mostly to the areas of Assam, Northeast India, eastern Tibet/Himalayas and Burma where Tantric forms of Mother Goddess worship became very popular.

That Polo refers to a word used in the 'language of those Isles' by the 'experienced pilots and mariners of those parts' is important.

Like the latter Portuguese explorers, Polo uses placenames for Southeast Asia that are mostly of local origin. He rarely uses Chinese or Muslim names, and this may indicate the nature of his informants, the pilots and mariners of those seas.

Insular Southeast Asian placenames

For example, Polo uses the form Ziamba (Ramusio) for Champa. This appears to come from the local Insular Southeast Asian Tsiampa, or related words like Ciampa (Javanese Cempa). The Arabic name for Champa was Sanf, while the Chinese called it Lin-yi.

The world Seilan for Sri Lanka might be derived from Javanese sela "jewel, which would match the Hindu Ratnadvipa "Isle of Gems" and the Muslim Jazirat al Yakut "Isle of Rubies."

In Poggio's account of the testimony of Nicolo de Conti, he also gives local names, rather than Chinese or Arabic ones, including the island of Bandam, the source of cloves, the first reference by native name to one of the Spice Islands (Banda).

Polo does use some Chinese names, for example, Mien for the Burmese kingdom rather than the Indian/Malay Barma. He seems to have learned about this kingdom through stories of Kublai Khan's conquest of Burma. The term Lequios used by the Portuguese comes from Chinese Liu-Kiu (Ryukyu).

When Portuguese and other explorers came into this region, they picked up many more regional names that appear to come from Insular Southeast Asian sources, many of which have survived in modified form until the present day:

Siam -- from forms like Cebuano Ciama or Malay Siyam.

Japan -- Japun, Japang, etc. ultimately from Chinese Jih-pen kuo.

Burma -- Barma, the Malay, Javanese and Indian forms.

Pegu -- Malay Paigu from Burmese Bago

Cochin-China -- Kuchi, Kochi possibly from Chinese Kiau-chih.

China -- Tsina, Tchina, from Qin (Ch'in) empire or Jin (Tsin) dynasty?

Champa -- Tsiampa, Ciampa, Cempa originally borrowed by Europeans as Ziamba, Ciamba, etc.

Moluccas -- Maluka a place on the island of Ceram.

Borneo/Burnei -- Brunei.

Luzon -- Lusung, Lusong recorded first by Tome Pires who calls the inhabitants Luções.

Banda -- first noted by de Conti as Bandam.

Informants

When Francisco Rodrigues arrived in Southeast Asia with the Portuguese in the early 16th century he collected information and charts from Javanese and other local pilots. Ludovico di Varthema did the same.

Later when the British began mapping the area, Alexander Dalrymple on many of his charts left notes specifying the sources of indigenous information often by name.

For example, on a chart of Borneo, Dalrymple notes that parts of the southern coast had not been "confirmed by any exact observation but is laid down from a Sketch of Dato Saraphodin and from a Chart of Noquedah Koplo who came up the Coast in 1761." On other parts of the chart he mentions features that were based on "Sketches I received from the Sooloos [Sulu], but chiefly from the information of Bahatol an old intelligent [Sulu] pilot."

The various informants supplied the placenames borrowed by early European explorers and cartographers resulting in many modern geographic names.

In a similar manner, Polo mentions receiving information from the mariners and pilots of the China Sea and Indian Ocean.

If we look at Polo's names for the Andamans, the Nicobars and Madagascar we may get some clues as to the provenance of his informants.

Instead of the Arab Lankabalus for the Andamans and Nicobars, Polo mentions Angaman and Necuveran, which along with Seilan remind one of the common use of the -an suffix for placenames in Insular Southeast Asia.

A short list of the numerous examples are: Dapitan, Palawan, Lingayan, Dagupan, Nunukan, Tarakan, Bataan and Bulacan. Thus, Seilan may be from sela-an, "place of jewels."

The name Madagascar may be confused with Makdashau (Mogadishu), but others would have it as a corruption of Malagasy.

The Arabic word for the island was al-Qumr, or sometimes Wak or similar terms, the latter probably stemming from the belief that the island was populated by the Wakwak from further east.

The mention of mariner's charts by Polo is also very informative. It was after Polo's return to Europe that the first extant nautical portolans appear. Although the Carta Pisana is sometimes dated to "circa 1296" or a year after Polo's return to Venice, and some believe it is even earlier, the first solid date for an extant portolan is the Genoese map made by Petrus Vesconte dated to 1311.

There is a vague reference to use of a sea chart by Raymond Lull in 1270 but it doesn't appear related to the explosion in the use of the portolan some 30 or more years later.

Lull's mention of sea charts and also the magnetic compass, like earlier references by Guyot de Provins and Jacques de Vitry in the early 13th century were probably based on tales from the Indian Ocean. Muslim writers mention fish-shaped floating compasses used by mariners in the Indian Ocean in 1242. These were almost certainly derived from similar compasses described by Shen Kua writing in the early 12th century but mentioning their use as early as 1086.

A south-pointing "fish" or "tadpole" is mentioned in the 4th and 10th centuries, and by the mid-11th century a specifically "floating" fish compass is mentioned in Chinese works.

De Vitry got much information from Arabic-speaking knights in his attempts to learn of the Mongol campaign, while Lull who grew up in Majorca and is said to have written in Arabic better than Latin. Both of these men may have received information from Muslim informants as they had great interest in the Muslim world.

None of the surviving confidently-dated 13th century European maps show signs of nautical application.

Gilbert the author of De Magnete says Marco Polo brought the compass to Europe from China, although Polo never mentions such a device himself. It could be that Polo brought the mariner's compass along with the mariner's chart, or quite specific but confidential information about both items.

Earlier loadstones may have been known in Europe since the 12th century, with stories of their application for navigation coming in the early 13th century from Muslim sources.

But is seems after Polo's time that we see the first hard evidence of the use of both mariner's compass and chart.

Unfortunately, little additional information exists of the Indian Ocean and China Sea charts until the Portuguese arrive in the early 16th century. It was at this time that Rodrigues reproduced Javanese maps covered with rhumb lines, one of which so deeply inpressed Albuquerque that he said, "it strikes me as the finest piece of work I ever saw."

Some years later, the Turkish admiral Piri Reis produced an extraordinary portolan of the world that was much different in its portrayal of the "New World" than other contemporary maps. Piri Reis claimed to use many charts as sources including those of Columbus, and also some Portuguese maps drawn using the "geometrical methods" of China and the Indies (Hind).

The Chinese "methods" probably refer to the rectangular grids that characterized Chinese maps, but what of those of the Indies? Was Reis referring to Portuguese sources like the now-lost Rodrigues chart with rhumb lines showing the navigation of the Indies?

Regards,
Paul Kekai Manansala
Sacramento

References

Ozdemir, Kemal, Ottoman Nautical Charts and the Atlas of 'Ali Macar Reis, Istanbul, 1992.

Polo, Marco, Henry Yule and Henri Cordier. The Book of Ser Marco Polo, the Venetian: Concerning the Kingdoms and Marvels of the East, Scribner, 1903.

Nicolo de Conti (Glossary)

Nicolo de Conti (ca.1395-1469), a Venetian merchant, traveled either 36 or 25 years, depending on which account you believe, throughout much of the Indian Ocean and the adjoining regions of Asia and Africa.

De Conti's great impact on history is seen through his account to papal secretary Poggio Bracciolini declaring that the Indian Ocean was a wide open sea and not enclosed by land as Europeans had thought since Ptolemy's time.

With good reason it is believed that de Conti's views influenced such persons and cartographers as Fra Mauro and Paolo Toscanelli. The latter in turn either directly or indirectly influenced both Columbus and Magellan in believing that one could venture to the East Indies from the East (traveling West from Europe).

African journey?

Gavin Menzies, in his controversial work on the voyages of Zheng He's fleet, has suggested that Conti had sailed with Zheng toward Africa, and beyond.

Menzies rightfully notes that Conti had great influence on cartographer Fra Mauro, a fellow Venetian. Mauro's map of the world uses place-names, and sources for spices, that appear directly copied from Conti's interviews with Bracciolini. Mauro also is the first to chart the difference between Taprobana (Sri Lanka) and Sumatra, something again first revealed in Conti's testimony.

Mauro also displays the Indian Ocean as an open sea with passage possible both in the East and the West.

The African connection comes from notes made by Fra Mauro concerning the voyage of a junk or ship from the Indies around the southern tip of Africa:

About the year 1420 a ship or junk of the Indies passed directly across the Indian Ocean in the direction of the Men-and-Women Islands beyond Cape Diab, and past the Green Islands and the Dark (Sea), sailing (thereafter) west and south-west for 40 days and finding nothing but air and water. According to the estimate of her (company) she travelled 32,000 km. Then, conditions worsening, she returned in 70 days to the aforesaid Cape Diab.

Fra Mauro continues in another passage again suggesting the continuity of the Indian and Atlantic Oceans, the former believed to be completely surrounded by land up until that time:

Moreover I have had speech with a person worthy of belief who affirmed that he had passed in a ship of the Indies through a raging storm 40 days out of the Indian Ocean beyond the Cape of Sofala and the Green Islands more or less south-west and west. And according to the calculations of her astronomers, his guides, this person had sailed 32,000 km.

Now, according to Menzies, the 'person worthy of belief' mentioned by Fra Mauro can be none other than Nicolo de Conti himself.

Conti had told Poggio, the papal secretary, that he left Italy in 1419 and using his chronology of events in that account it appears he made his way to India and left from there either in 1421 or 1422 i.e. very near the 'about the year 1420' mentioned for the African journey by Fra Mauro.

Menzies believes that Conti departed India with Zheng He's fleet. The next thing we hear from Poggio's account, though, is that Conti is in Sumatra and there is no mention of an African journey.

Scholars have suggested that Poggio censored Conti's account (see Rubiés, p. 121), and that may have some confirmation when we see the difference between Poggio and Tafur's versions of Conti's journeys.


Three Indias

Conti divided India into three parts as was common in his time. The first India was found from Persia to the Indus River, the second from the Indus to the Ganges, and the third included all the lands beyond the Ganges i.e., India extra-Gangem.

He described India beyond the Ganges as "far surpassing others in wealth, kindness and magnificence, and equaling us in customs and civilization" ("...est opibus, humanitate, lautitia longe praestantior, vita et civili consuetudien nobis aequalis.").

It also should be noted that Fra Mauro describes the African voyage ship that Conti supposedly traveled on as a 'ship or junk of the Indies.'

That's an interesting description because at this time, Southeast Asian ships often were of a hybrid type showing both junk-like characteristics such as transverse bulkheads, and Southeast Asian typology including wooden joints and tropical hardwood materials rather than the fir commonly used to construct Chinese junks.

Even the word "junk" or "zoncho" (Portuguese junco) appears derived from Old Javanese jong and Javanese djong, a name for an ocean-going ship.

Conti himself in his testimony to Pero Tafur had stated that he spent most of his time in the Indian Ocean in the service of "Prester John" of "Greater India."

One interesting discovery has been highlighted by Menzies as proof that ships at that time were circumnavigating the world. The Pandanan wreck off the coast of Palawan in the Philippines is dated to the 15th century and is loaded with andesite metates that Menzies claims must have come from Mesoamerica or South America. The cylindrical stone manos of the metates are rather unusual and do resemble those of the contemporary period "New World."


15th-century Pandanan wreck metate and mano. Source:
http://users.telenet.be/joosdr/amerika/eeuwamerika228.htm

The lusung/lusong mortars and pestles in the Philippines are generally made of wood. In Guam, the Chamorro lusong is stone, but the pestles are wood. Nothing quite similar to the Pandanan metates is known to have been manufactured in this region during the historical period.

Like other ships of that time and in the same region, the Pandanan wreck shared characteristics of both Southeast Asian and Ming-era Chinese ships.

Fra Mauro's map shows junk-like vessels with high stern and square bow plying the Indian Ocean, along with details of what apparently is the island of Madagascar and the Cape of Good Hope.

Mauro describes the ships that crossed the Indian Ocean in these terms:

The ships or junks that navigate these seas carry four or more masts, some of which can be raised or lowered, and have 40 to 60 cabins for the merchants and only one tiller. They navigate without a compass, but have an astrologer who stands on the side and with an astrolabe in hand, and gives orders to the navigator.

This does not appear to describe Zheng He's fleet or other Chinese merchant ships at the time, which did use the compass for navigation. Arab ships also began to use the compass by the 12th century at least. As noted earlier most ships of Southeast Asia did not use the compass when the Europeans arrived on the scene, but the "astrolabe" mentioned above was not commonly used either. The single tiller brings to mind the axial rudder as found on junks or hybrid ships.


Junk-like ship with four masts from Fra Mauro's map positioned west of Sri Lanka in the Indian Ocean. Tracing from: De Santarem, M. Visconde. Atlas Compse de Mappemondes et de Cartes Hydrographiques et Historiques, Maulde and Renou, Paris, 1895.

Prester John

Conti tells Tafur that he had personally witnessed Prester John send two missions to 'Christian princes' but had not heard whether these had met with success. The king was also said to have been making preparations for a visit or conquest of Jerusalem. These reports indicate that Conti's Prester John was involved in long-range maritime missions.

Unfortunately Conti's account gives us little information useful in locating this Prester John of the Indies. In his interviews with Poggio, he is aware of the then-existing claims of both an "Indian" and an Ethiopian Prester John. Tafur makes it clear that the Prester John of Greater India is distinct from that of Ethiopia, when he talks of the varying complexions of people in both regions.

Conti mentions a Nestorian king who lived somewhere near Cathay along with the Ethiopian king, and Poggio is said to have interviewed emissaries from the East after his discussions with Conti.

Poggio describes the eastern ambassador as coming from "Upper India" as an envoy of a Nestorian kingdom located 20 days journey from Cathay.

'Upper India' during Poggio's time meant the same as 'Greater India.' With Lower, Middle and Upper India corresponding to the West to East order and Upper India referring to the region beyond the Ganges.

We have seen during this period that the kingdom of Lusung was practicing a policy of attraction with the Ming dynasty, and at the arrival of the Portuguese they were well-dispersed throughout Southeast Asia and eager to provide navigational assistance to the newcomers.

Toscanelli, a friend of Poggio, also met with the Eastern ambassador but he confuses his kingdom with that of Marco Polo's "Great Khan," which by this time had faded into history.

Columbus in his annotated copy of Historia rerum with his own notes copies Toscanelli's letter to Martins referring to Nicolo de Conti's testimony.

Magellan, when faced with a doubtful crew near the tip of South America, told them of a chart he had seen made by Martin Behaim displaying a passage to the Pacific Ocean. Behaim also appeared to have been strongly influenced by Toscanelli as his famed Behaim Globe is nearly a copy of Toscanelli's reconstructed chart.

As Toscanelli himself was indebted to Conti (and also possibly to the Eastern ambassador), it can be said that few persons so influenced the European age of discovery as Nicolo de Conti.

Regards,
Paul Kekai Manansala
Sacramento

References

Larner, John. Marco Polo and the Discovery of the World, Yale University Press, 2001, p. 9.

Rubiés, Joan-Pau. Travel and Ethnology in the Renaissance: South India Through European Eyes, 1250-1625, Cambridge University Press, 2002, p. 93.

Menzies, Gavin. 1421: The Year China Discovered America, HarperCollins, 2003.

Vignaud, Henry. Toscanelli and Columbus: The Letter and Chart of Toscanelli on the Route to the Indies by Way of..., Sands & Co., 1902.