The Islamic Role in Nautical Discoveries: Reassessing Mainstream Modern History 


Contrary to what most historians dealing with maritime discoveries hold, nautical science, like every other scientific accomplishment and manifestation, did not die or disappear for nearly fifteen centuries to suddenly re-appear in the 12th century, through the rediscovery of Ptolemy, or Aristotle, or to reappear in the later Renaissance (16th century) thanks to the Iberians. As Dunlop correctly points out:

‘The Arab empire at its greatest expansion in Umayyad and early 'Abbasid times (8th century) extended from Spain in the West to China  in the East, and in round terms this is the fact, but perhaps the extraordinary outward thrust of the Arabs in the seventh century is conveyed best to the imagination by emphasizing the maritime activity of the same nation at the same time off the Atlantic and Pacific coasts of Eurasia. This was a phenomenon which had scarcely as yet been seen, and pointed forward to the achievements of the great colonial empires of modern Europe.’[1]

Centuries, indeed, before Western Christendom, Muslim ships crisscrossed the seas in, and surrounding, that vast empire, reaching parts and distances never reached by their Western counterparts, and in doing so, bequeathed not just new practical knowledge of the art, but also an abundance of original written material of varying sorts, which formed the foundations of the maritime discoveries of the modern era.


Early sea travels by the Muslims are abundant in density and diversity, and they had a wide reach all over the continents. The sailing trips to China , South East Asia, the African coastline, in and out of the Arab Peninsula, in and out of Alexandria, or in and out of Andalusia and Muslim Spain have been abundantly seen (above and in part one) and do not warrant detailed repetition here. Briefly, Muslims had, in earnest, explored the area between Ceylon (Sarandib) and the west coast of India .[2] Ships sailed between the Arab peninsula west to the east coast of Africa (the fief of Oman), with its 37 ports located in modern Kenya, Mozambique and Tanzania, and east in direction of the Sultanate of Delhi.[3] In 1420, a Muslim ship went round the Cape, and entered the Atlantic, which was about sixty eight years before the Portuguese reached the Cape.[4] Atlantic sailing had, in fact, begun much earlier according to an account by al-Idrisi. He tells of a voyage of a group of Muslim sailors called al-Mugharirrun (the Adventurers) of Lisbon into unknown lands in the 9th century.[5] Guided by favourable winds, they reached as far as the Polar Regions, and possibly knew of a land beyond the Atlantic Ocean.[6] A Muslim party had also sailed to Scandinavia, to the Viking court around the middle of the 9th century, and more did so thereafter as already seen above. Muslims also knew of the British Isles (twelve in numbers according to al-Battani with Inkiltara (England), Squsia (Scotland) and Irlanda (Ireland).[7] They described whaling in the vicinity of Ireland[8] and seal fishing in the  Atlantic Ocean.[9] To the south of Spain, they reached the Canaries and the Cape Verde Islands centuries before their immediate successors the Portuguese.[10]


This sea and ocean going opened the way to a vast, and early, scientific knowledge of matters related to navigation. Abu Ma’shar (d. 886), for instance, shows a knowledge of the monsoons of the Gulf and the seas of India , and he writes about the causes of the ocean tides and currents.[11] This knowledge was of great importance to the navigators of his day, and he was prolifically quoted by Roger Bacon in his Opus Majus.[12]

Likewise, in his travels to China , Suleiman (9th century), was able to make a remarkable observation, that the seas of India , Persia , and the Mediterranean  form a block of water. He says:

‘Among the things that have happened in our days, and were not known were these: It was not conjectured that the Chinese Sea and the Indian Ocean  were not connected with the Syrian sea, nor had the sailors of bygone days any such idea. But this was proved in our time. For we received a report that the timbers of ships wrecked in the Mediterranean  Sea, and shattered into pieces by the waves, were carried into the Khazar Sea by the wind and from there came to the Mediterranean Gulf, and after that to the Mediterranean and Syrian Seas. This proves that the Sea lies round China , Seuila at the back of Turkestan and Khazar, and then drifting into the Mediterranean Gulf flows to the Syrian coast.’[13]

Al-Yaqubi, too, notes in his description of the Moroccan coastal town of Sos:

‘In front of this Mosque  (Bahlol), the sea brings forth those rope fastened ships, which are built in Obulla (Gulf) and in which they voyage to China .’[14]

This matter is further studied by Al-Biruni , Abu Hamid of Grenada , Abu’l Fida, Ibn Khaldun  etc.[15] Its impact, other than the noted fact of the seas being interconnected was that:

a.) It opened a completely new vision of the shape of the world, and that stirred a renewed spirit of enquiry, in places shattering hitherto accepted wisdom.

b.) It also brought forth the idea that, once various parts of the earth were linked by water, sailing east could take one to a point in the west; and vice versa. The implications of this are well known. 


As early as the 10th century, Muslim sailors and learned men such as al-Biruni, had also acquired an excellent knowledge of two major sea and ocean routes.[16] One route led them from the Arabian Sea to the Chinese Sea, then to the North Pacific Ocean; entering the Bering Sea, out through the Arctic Ocean, into the Atlantic, through Gibraltar into the Mediterranean . The second went from the Indian Ocean  to the Abyssinian Sea, down through the Mozambique Channel, to the Cape of Good Hope, passing by the African coast, to the Atlantic Ocean via the Cape of Gibraltar, and then entered the Mediterranean Sea.[17] 


A crucial development arose from this sea and ocean going, and relates to the pioneering findings of al-Biruni. Until his time, the overall concept that prevailed was of an unknown land connected with South Africa, but al-Biruni put forward the concept  of the existence of a sea passage between south Africa and the unknown land.[18] Abul’l Fida (1273-1331) incorporated this concept in his Taqwim al-Buldan, and it is possible that the Portuguese navigators and explorers of the later period may have had the idea of an entrance to the Indian ocean from the work of Abu’l Fida, which might have reached Tangiers  about this time.[19] 

It is also established, through Frau Mauro, who drew a world map in 1457, that an Arab navigator had, in 1420, sailed from the Indian ocean into the Atlantic, around the Cape of Good Hope.[20] The great world map completed at Venice in 1459 by Fra Mauro, with Bianco’s assistance, appears to give little more information for West Africa. East Africa is represented in some details, perhaps from Islamic sources, and Fra Mauro explicitly repudiates the Ptolemaic concept of a land locked Indian Ocean , showing an open seaway round the southern point of Africa.[21]


There was a further Islamic impetus to nautical advance in the use by Islamic sailors of instruments for navigation purposes. According to Ibn Majid, the mu'allims, the master pilots famous in the 10th century under the Abbasids , used the astrolabe in their seafaring expeditions.[22] The portable astrolabe was used by navigators for measuring altitudes until the 17th century, whilst the ruba was used for measuring the angles.[23] The compass, which most certainly was a Chinese invention, was turned by the Muslims into an essential element of navigation,[24] used for finding direction.[25] In respect to the latter, Nadvi reminds us how as early as the 9th century, Muslim sailors of the Arabian sea referred to the dai’ra (circle) and to the beit of al-ibra’a (Abode of the Needle.)[26] The sundial was used for calculating daily time and the azimuth (compass bearing).[27]


Early on, Muslims pioneered in the adaptation of exact sciences to navigational purposes. This includes precise surveys of the oceans, steering ships clear of gales and storms, familiarity with the direction of winds, great knowledge of nautical astronomy, especially as, among the navigators were many astronomers and mathematicians who prepared sea charts, and who calculated the length and breadth of the oceans.[28] This science also includes first-rate representations of the coastlines, as of the Indian Ocean  by Ibn-Majid and al-Mahri.[29] Ibn Majid, according to Portuguese sources, was in possession of a very good sea map and other maritime instruments.[30]


The portulan (nautical chart) was crucial to the progress of navigation, helping the pilot find with extreme accuracy the ship position, and determine precisely the direction to follow to reach a determined point.[31] The origin of portulans is dated by Saunier Site at between the late 11th and early 12th century, the work of al-Idrisi at the Norman Court.[32] Miquel, however, dates them to the end of the 9th century.[33] Grosset-Grange, for his part, holds they were not much in use in the earlier stages of navigation, but adds that although such Muslim charts are lost, the Portuguese did see them.[34] Kimble points out that the supposition that there may have been Muslim charts in earlier centuries is not entirely without foundation, for Marco Polo confesses that he drew his knowledge of the coast of Ceylon from the ‘charts of the mariners of those seas.’[35] And Ramon Lull, writing about the same time, refers to the practice of sailors carrying chart and compass.[36] From Muslim sources, we learn that there were already in the early 11th century professional writers of nautical instructions. The earliest dated pilots were Ahmed Tabruya, and Al-Arki (the latter sailing on an Indian ship in the year 1009-10), who wrote on navigation, and whose works were used by subsequent master pilots.[37] Sahl Ibn Aban, Mohammed Ibn Shadban, and Laith Ibn Kahlan to name only three, were also writers on the subject, and the date for these three, according to Tibbetts, could be the end of the 11th or early 12th century.[38] Al-Muqaddasi (10th century)[39] also claims to have seen a paper map in the library of the Samanid ruler of Khorassan, and another in Nishapur, and in two other libraries. Each was different from the other. He says:

‘I have wandered on the Arabian coast from the Mediterranean  to Abadan, besides those islands where ships stopped to take water. I have met those old mariners, who were born and brought up in this sea. They were skippers, passenger stewards, mathematicians, agents or merchants. Their knowledge of the seas, harbours, winds and islands was more reliable than those of any other men, so I asked them of the sea and its boundaries, and argued with them. They had a large number of files and books, on which they relied, and they act according to the directions given in them. I copied many things from them and compared their maps with mine.’[40]

The Islamic impact in respect to portulans is obvious, and subsequent charts developed in Europe had Islamic sources.[41] The Genoese, for instance, used earlier Muslim treatises of Ibn Hawqal and al-Bakri to devise their portulans.[42] As De la Ronciere explains, the Genoese learned the arts of navigation from the Sicilians in the early 13th century and transmitted them subsequently to the Spaniards, Portuguese, French, and English; and a new science of the seas was developed upon the foundations originally laid by Sicilian Muslims and Normans.[43] De la Ronciere concludes that the use of coastal charts was destined to become general in Sicily , a rational method of navigation to be substituted for the routine of pilotage, and thus the way was prepared for the progressive conquest of the world.[44]


Much knowledge relating to the Indian Ocean  was also derived from Islamic nautical treatises.[45] Carra de Vaux points to the modern studies by Ferrand and Demombynes on nautical instructions left by Muslim pilots at the end of the 15th century.[46] The instructions, de Vaux notes, served as a basis to those of the Portuguese pilots of the following century. They are, he says, in prose and in verses, and can be found in Arab manuscripts of the French National Librarie (Bibliotheque Nationale).[47] The two main authors of such manuscripts are Ibn Majid (the author of more than thirty nautical treatises, according to Miquel)[48] and Suleiman al-Mahri. They were the result of the two men’s first hand ocean experience.

Ibn Majid (d. early 16th century) belongs to a family of navigators from Oman, both his father and grandfather being mu’allims (masters of navigation,) and he, himself, sailed most of his life on the Indian Ocean , its gulfs, and the Red Sea, gathering experience and knowledge of navigation, both in theory and practice, his works were to serve as guides to future navigators in the Indian Ocean.[49] Ibn Majid did not just rely on his experience, but also on earlier works on the subject, including those by the famed three mu’allims of the Abbasid period, Mohammed b. Shadhan, Sahl b. Aban. And Layth b. Kahlan.[50] He produced a number of works on the subject, including his Kitab al-Fawaid fi usul ilm al-bahr (Treatise on Nautical Sciences), dated 1489-90.[51] He gives useful information on the principles of nautical science, and also describes the large islands such as Madagascar, Java, Sumatra, Ceylon, etc.[52] In this work, Ibn Majid also describes the sea coasts of the then known world (Asia, Europe and Africa) which no other geographer, with the exception of Al-Biruni , to some extent, did before him.[53] Ibn Majid is also the author of  al-hawi (the Compodium), dated 1462, which discusses wind directions, sea routes, coastal roads of Arabia  and other places, distances between ports, latitudes of ports on the Indian Ocean and so on.

Suleiman al-Mahri is a younger contemporary of Ibn Majid, who flourished early in the 16th century, and who is the author of five works on navigation, preserved in a manuscript of the Bibliotheque Nationale Paris (MS. No 2559).[54] His largest work is al-Umdat al-Mahriya fi dabt al-Ulum al-Bahriya, written in 1511, a treatise that includes fifty folios, and seven chapters dealing with: 1.Principles of nautical astronomy; 2. The stars and navigation; 3 and 4. Sea Routes; 5. Qisayat; 6. On Seasonal Winds; 7. On the Red Sea. It includes subjects related to names of stars, sea routes, islands and how to reach them; latitudes of places from observation of the polar star; monsoons; itineraries along the African coast; the seas of Western China  and Indonesia, etc.[55] His second large work is Kitab Minhaj al-Fakhir fi ilm al-Bahr, also in seven chapters, included coastal regions of the Indian Ocean ; ports; large islands; distances between Arab countries, the coastal regions of India , winds, storms, signs of land, and in conclusion, the five sea-routes.[56]  

Whilst sojourning in the Gulf in 1553, the Turkish  admiral, Sidi Ali Tchaleby gathered Arab writings on nautical instructions, and had them translated into Turkish in a treatise entitled ‘The Mohit, and what surrounds it'.[57] The Mohit is divided into an introduction and nine chapters, including subjects such as the distance of the stars and their altitudes, the calculation of time, calendars of different nations, division of the needle box, sea routes, terminology of the art used by sailors, seasonal winds, dangers that might accrue to sailors, and also the New World (i.e America).[58]


Islamic superior seafaring is further demonstrated by the fact that in the 14th century, some of the officials responsible for the Chinese navy were Muslims, notably the famed admiral Zheng He (Cheng Ho), whose father had even been on pilgrimage to Makkah .[59] The Portuguese, too, had large recourse to Muslim pilots, as can be amply shown in chronicles and other governmental sources.[60] Gaspar Correia, for instance, asserts that following his first trip East, Vasco de Gama brought back to Portugal Muslim pilots, whom he lodged in his own house, and to whom he had recourse for the preparations of the fleet of Cabral.[61] Albuquerque’s commentaries also make many references to the widespread use of Muslim pilots, generally those embarked in 1507 at Melinde, Socotora, and Orfacao.[62] 

Portugal was no China , though; and, as to be seen in the final chapter of this work, Ibn Majid guiding in 1498 the Portuguese fleet to Calicut in India  (in present Kerala state),[63] was going to be very costly for the Muslims, destroying their supremacy in the region. Arab sources of the time state that he was induced to show the way to the Portuguese only after having been made drunk.[64]


Finally, Columbus' discovery of the New World is owed to earlier contribution by Islamic nautical science as noted by Kramers.[65] Kramers explains that the discovery owes much to the idea that the known hemisphere of the world had a centre or ‘world summit' which was equally distant from east, west, north, and south, referred to by Al-Battani  as the ‘cupola of the earth' (Qubbat al Ard in its Arabic original), whilst Ibn Rusta refers to it as the ‘cupola of Arin'. The word Arin itself is a misreading of the Arabic transliteration of the name of an Indian town. Adelard of Bath, Gerard of Cremonna, Roger Bacon and Albertus Magnus, considered this Arin theory of the highest importance, which was later to be found in the Imago Mundi of Cardinal Peter of Ailly published in 1410. From this book Christopher Columbus learnt the same doctrine, to believe that the earth had the shape of a pear, and that, on the western hemisphere, opposite the summit of Arin, was another centre, much higher than the one on the eastern side, thus forming the shape of the lower half of a pear. This induced him in his sailing experience when all around him was against it. What followed his successful attempt is well known.


This chapter has abundantly shown the vast and pioneering Islamic role in nautical science and seafaring. Yet, this is what Hartmann, expressing a widely established view, writes:

‘Islam has as a rule been afraid of the sea; from the very beginning it was impressed with a sense of the supremacy of the unbelievers on the Ocean and made practically no efforts to dispute their domination.’[66]

[1] D.M. Dunlop: Arab Civilisation; op cit; p.160.

[2] J.H. Kramers: Geography, op cit, p. 95.

[3] Henri Grosset-Grange: Arabic, op cit, p 203.

[4] Ibid.

[5] Abrege par  Gabriel Sionite, Geographia Nubiensis (Paris, 1619), p. 157, in Baron Carra de Vaux: Les Penseurs, op cit, pp. 47-9.

[6] M. A Kettani: Science, op cit,  p. 82.

[7] C. Nallino: Al-Battani  sive Albatenii Opus Astronomicum (Milan, 1903), Arabic text, 26; Latin  tr. 18. in D.M. Dunlop: Arab Civilisation, op cit, at p. 160. 

[8] Qazwini, ed. Wustenfeld, ii, 388; Eng. tr. in D. M. Dunlop. ‘The British Isles According to Medieval Arabic Authors', Islamic Quarterly, iv (1957), pp 11-28 at pp 19-20.

[9] Al-Maqqari: Nafh-al-tib, ed Leiden, i, 121-2; in D.M. Dunlop: Arab Civilisation, op cit, p. 162.

[10] In S. Nadvi: Arab Navigation , op cit, pp 87-8.

[11] Abu Ma’shar: Al-Madkhal al-Kabir; Ms. No A. 1504; Arabic Society Library; Calcutta; fol 62.

[12] S.M. Z. Alavi: Arab Geography; op cit; pp. 21-2.

[13] S. Nadvi: Arab Navigation ; op cit; pp 74-5.

[14] Ibid; p. 76.

[15] Ibid; pp 76-84.

[16] Ibid, pp 87-8.

[17] Ibid.

[18] S.M. Ahmad: History; op cit; pp. 236-7.

[19] Ibid.

[20] I.J. Krckovskij: Izbrannye Socinenja,. Op cit; p. 5 62.

[21] L. Bagrow: History; op cit; p. 105.

[22] In Carra de Vaux: Les Penseurs; op cit; p.67.

[23] A. Buang: Geography in the Islamic world; in Encyclopaedia (Selin ed): pp 354-6: at p.356:

[24] W. M. Watt: The Influence, op cit, pp 20-1.

[25] A. Buang: Geography in the Islamic world; op cit; at p.356:

[26] S. Nadvi: Arab; op cit; p.111.

[27] A. Buang: Geography in the Islamic world; op cit; at p.356:

[28] S.M.Z Alavi: Arab Geography, op cit, p. 52.

[29] Henry Grosset Grange: Arabic, op cit,  p. 221.

[30] J.H. Kramers: Geography, op cit, p. 96.

[31]A.Teixeira da Mota: Methodes de navigation et cartographie nautique dans l'Ocean Indien avant le XVI The Global Opportunity; ed by F.F.Armesto (Variorum; Ashgate Publishing; London;  1995), pp. 44-91, at p. 56.

[32] A. Saunier Seite: De la Geographie Grecque a la Cartographie occidentale du XVII siecle; Acta Geographica;  No 101 (1995);  pp 3-18; at p. 7

[33] A. Miquel: Geography, op cit, p. 811.

[34] H Grosset-Grange: Arabic Nautical Science, op cit; p. 220.

[35] The Book of Ser Marco Polo; vol; 2; pp. 312-3 in G.H. T. Kimble: Geography in the Middle Ages; op cit; p. 190.

[36] Vide Arbor Scientific (written 1300) (Lyon edition 1515), fol cxci.

[37] G.R. Tibbetts: Arab Navigation  in the Indian Ocean ; op cit; p. 2.

[38] G.R. Tibbetts: Arab Navigation ;  pp. 4-5;  and  G. Sarton: Introduction; vol ii; p. 221.

[39] Al-Muqaddasi: Ahsan at-taqasim; op cit.

[40] Ibid; p. 10.

[41] W. M. Watt: The Influence, op cit,  p 21.

[42] J.H. Kramers: Geography, op cit, p. 98.

[43] De La Ronciere: Marine Francaise; vol 1; 1909; p. 136-7 in J.K. Wright: The Geographical Lore of the Time of the Crusades (Dover Publications; New York), 1925; p. 81

[44] Ibid.

[45]  C. de Vaux: Les Penseurs de l'Islam, op cit, chapter ii, pp. 41-74;

[46] The outline of the publication includes four volumes; the first two include the reproduction of the nautical instructions of Ibn Majid and Soleiman al-Mahri. The third includes the translation of the reproduced geographical parts of the manuscripts and a glossary of nautical expressions. Part IV is the translations of some ancient Portuguese seafarers. ‘From the comparisons of these seafarers with previous Arab texts, the document says, it comes out that these have been established after Arab originals.''  

[47]  C. de Vaux: Les Penseurs de l'Islam, op cit, chapter ii, pp. 41-74;

[48] A. Miquel: Geography,  op cit,  p. 811.

[49] S.M. Ahmad: History; op cit; p. 234.

[50] Ibid.

[51] Ibn Majid: Kitab al-Fawaid; published by I. Khuri and I. Hasan (Damascus ; 1971);

English translation by G. Tibbetts: Arab Navigation  in the Indian Ocean  before the Coming of the Portuguese (London; 1971).

[52] Carra de Vaux: Les Penseurs; op cit; pp 72-4.

[53] S.M. Ahmad: History; op cit; p. 234.

[54] I.J. Krckovskij: Izbrannye Socinenja,. op cit; pp. 630-1.

[55] Ibid.

[56] Ibid. See also S.M. Ahmad: History; op cit; pp. 246-7.

[57] Hammer Purgastall: extracts from the Mohit, that is the Ocean, a Turkish  work on navigation in the Indian seas, in Journal of Asiatic Soc of Bengal, vols iii to viii (1834 to 1838).

See in the same collection J. Prinseps: Note on the Nautical Instruments  of the Arabs, vol ii, 1836.

[58] I.J. Krckovskij: Izbrannye Socinenja,. op cit; pp. 635 ff. See also S.M. Ahmad: History; op cit; pp. 248-50.

[59] A. Pacey: Technology ; op cit;  p.55.

[60] T.A.da Mota: Methodes; op cit; p. 52.

[61] G. Correia: Lendas da India ; Lisboa; 1858-1866; Vol 1; part 1; Gama ch xxii; Cabral Ch 1; in T. A da Mota: Methodes; op cit; p. 52.

[62] In T.A.da Mota: Methodes; op cit; p. 52.

[63] Henri Grosset-Grange: Arabic, op cit,  p 203.

[64] J.H. Kramers: Geography, op cit, p. 96.

[65]  Ibid; pp. 93-4.

[66] M.Hartmann: China ; Encyclopaedia of Islam; 1st series; Vol 1 (Brill; Leiden;  1913), pp. 839-54; at p. 844.