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.
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?
Paul Kekai Manansala
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.