Indian Ocean navigation in Islamic sources 850-1560 CE
1 | INTRODUCTION
There has been considerable historiographical focus on the oceanic expansion of Europeans, particularly into the Atlantic, and on the development of sustained trade routes between Europe, Africa, and the Atlantic in the late fifteenth and sixteenth centuries. The °Age of Discovery” has captured the popular historical imagination for over a century and celebrated the exploits of Prince Henry the Navigator, Christopher Columbus, and Ferdinand Magellan. This narrative has asserted considerable influence on the study of maritime navigation and focused scholarly attention primarily on European navigational developments. Consequently, the importance of the Indian Ocean only emerges when Vasco da Gama enters its waters in 1498, and connects it to the global maritime trade routes first established and maintained by Europeans.
With the rise in popularity of °world history” in the last three decades, however, there has been a corresponding "thalassological turn," as historians have worked to provide a more global examination of maritime activities that extends beyond the dominant Eurocentric narrative. Ocean-based histories have become particularly prominent, creating networks of scholars devoted to historical oceanic "worlds," such as the Atlantic World, or the Pacific World, to counter the perceived limitations of traditional, land-based regional studies. This has led to corrective meta-narratives that includes the navigational achievements of non-European mariners such as the Polynesians, Chinese, Arabs, and Persians.
One result of this new dynamic has been a remarkable growth in the field of Indian Ocean studies over the last two decades. Numerous academic monographs and edited volumes have been published about the Indian Ocean, and conferences on the topic are convened each year. In addition, new centers have emerged to create institutional support for studying the littoral societies along its shores. This is a commendable and much needed corrective to the previous land-based, area-studies approach that limited our understanding of maritime connections across broader geographical areas.
Despite the rising popularity of Indian Ocean studies, research focusing on the development of navigation in the western Indian Ocean currently suffers from a surprising degree of scholarly neglect. By “navigation,» I mean the specific technical skills and environmental and astronomical knowledge required to guide one across the seas. Thus, although there exists a considerable corpus of literature pertaining to trade routes and monsoonal sailing patterns, written works that focus on scientific texts about maritime navigation are much more limited. This article will provide a brief historical description of the development of navigation in the Indian Ocean, with a particular focus on Islamic sources from the period 850-1560 CE. It will then discuss the general historiographical development of the field of Indian Ocean navigation up to the present day, before concluding with suggestions for future research and historical inquiry that could significantly enrich our understanding of Indian Ocean navigation.
2 | THE ENVIRONMENT
The Annales School of history has had a major impact on maritime history, particularly because of its emphasis on the longue durée importance of the natural environment in shaping human activity. Almost every work in the field of maritime history since Fernand Braudel's magnum opus, The Mediterranean and the Mediterranean World in the Age of Phillip II, has begun with a description of the physical characteristics of the relevant body of water, and its surrounding coasts. In some cases, this has become an overused trope, but in the case of navigational history, it is required. Navigation involves the practice of human conceptual and physical interaction with the natural environment in order to travel from one place to another. As such, the contours of the body of water being traversed profoundly influence the maritime navigational practices used to move across its surface.
This is certainly true for the Indian Ocean, which contains approximately one-fifth of the surface area of the world's oceans, and consists of a wide variety of coastal environments and ecological zones. For most of human history, the primary maritime trade routes have been located along its northern half, from the upper reaches of East Africa to the southern coasts of Asia and Southeast Asia. By the ninth century, these maritime trade routes—often referred to as the Maritime Silk Route—extended well beyond the Indian Ocean into the South China Sea, making it the longest maritime route in the world until the late fifteenth century. The specific characteristics of these marine environments shaped almost every aspect of navigational practice, from star lore to navigational techniques and technologies.
Among the Indian Ocean's most remarkable features is its annual cycle of monsoons. These relatively regular, alternating winds in the northern portion of the Indian Ocean allowed for seasonal movement back and forth along and between its shores. The predominant literature divides the monsoons into two main seasons: that of the northeast monsoon blowing from the Asian landmass towards the south in the winter months; and the stronger southwest monsoon, driving northward and creating rough and fearsome seas at its height in the middle of summer. However, within this broad bi-seasonal annual pattern, there are a host of countervailing regional winds and other sailing seasons that navigators were aware of and used to their advantage. Much sailing was done in between the two monsoons at the beginning or end of the main seasons. Sailing eastwards across the Bay of Bengal, for example, one needed to depart in late April or May when the rather unstable southwest monsoon had just begun, but before it had truly gained force.
3 | HISTORICAL DEVELOPMENT OF INDIAN OCEAN NAVIGATION
Within the broad environmental parameters of the Indian Ocean, maritime societies adapted a variety of techniques and practices to help them travel safely in such a potentially dangerous environment. This discussion of that subject focuses on the period between 850 and 1560 CE, when literature relating to navigation in the Islamic tradition emerges, elucidating a sophisticated body of knowledge, with a strong emphasis on stellar celestial navigation. After 1553, the record becomes silent once again for a period, before it re-emerges transformed as a profoundly more solar-based, sextant-oriented series of practices in the eighteenth-through-twentieth centuries. Unfortunately, our understanding of the early historical development of Indian Ocean navigation is extremely limited and suffers from a paucity of evidence. Although the Periplus Maris Erythraei (a mid-first century CE sailing manual)—along with brief references in other early texts, and tantalizing hints in the iconography—provides clues to navigational practices, it is not until the Islamic period that a detailed navigational literature emerges. Geographical texts relating to maritime routes first appear in the ninth century, and by the fifteenth and sixteenth centuries, a significant collection of navigational texts enters the historical record. These texts, primarily written in Arabic, provide us with a much more detailed understanding of navigational practices in the Indian Ocean. They are comprised primarily of the works of two Arab navigators: Ahmad ibn Majid in the fifteenth century, and Sulayman al-Mahri in the sixteenth century; and a later Ottoman work in Turkish by Sidi Raʾis, al-Muhit (the Ocean).
Although it is beyond the scope of this article to discuss the origins of Indian Ocean navigation in detail, a brief summary of its general development and main concepts is necessary. Archaeological evidence suggests that maritime trade in the Arabian Gulf developed from at least the Ubaid Period (6000-4300 BCE) as the pre-historic sailors grappled with the elements in order to travel by sea. Inevitably, they relied strongly on what is now referred to as natural navigation—the use of a variety of environmental markers (known as ishârât or ʿalāmāt in Arabic) and weather patterns without the assistance of instrumentation to guide them along the correct route, and typically within the sight of land. Thus, early navigators used mountain tops, wave direction, and specific types of marine flora and fauna to determine their approximate location. In addition to these techniques, early Bronze Age sources also describe the practice of keeping caged birds on board, and then letting them loose and following them as they flew towards land—suggesting that even at that early date, some sailing was done beyond the sight of land .
Mariners also developed a keen understanding of the seasonal variations of the winds, in order to effectively harness their power. Eventually, they used these winds to sail directly across the western Indian Ocean. An anonymous Greco-Roman sailing guide, the Periplus Maris Erythraei mentioned above, states that a certain Greek navigator, Hippalus, was the first to sail straight from Arabia to India at the end of the first millennium BCE . Some historians have relied on this text to argue that the Greeks were the first to establish a deep-sea route across the Arabian Sea, while other historians believe that indigenous navigators had been sailing the route prior to Greek entry into the Indian Ocean and that Hippalus was merely the first Greek to be recorded making the journey . It is clear that by this period, if not earlier, mariners were using the monsoons to regularly sail back and forth across the Arabian Sea, purposefully venturing far from land to reach their intended port . However, although there is historical and archaeological evidence for these voyages, references to specific, technical navigational practices are extremely limited.
It is not until the later part of the Early Islamic period (622-1000 CE) that a corpus of geographical literature emerges that provides more detail regarding the maritime routes between East Africa and China. Afro-Asian maritime routes across the Indian Ocean into the South China Sea had existed in a rudimentary form prior to the Islamic period, but these routes become much more frequently and regularly travelled in the eighth through tenth centuries as the economies of the Islamic Abbasid Caliphate and Tang China intertwined via their maritime networks. By the ninth and tenth centuries, Muslim geographers such as Abu Zayd al-Sirafi, `Ali b. al-Hasan al-Mas'udi, and Muhammad b. Ahmad al-Muqaddasi provide descriptions of routes, seas, tides, and seafaring communities. It is also apparent that stars were being used to determine bearings. In addition to using the Pole, or North, Star, this practice involved employing a collection of the brighter and more prominent stars whose risings and settings constituted specific directional markers (rhumbs).
However, it is not until the fifteenth and sixteenth centuries that we encounter a sophisticated body of literature that provides a detailed chronicle of navigational practices beyond a mere description of the routes and the occasional reference to specific practices or instruments. The fifteenth‐century Arab navigator Ahmad ibn Majid, reportedly from Julfar in the Arabian Gulf, and the son of a Red Sea pilot, wrote over forty works on navigation. The vast majority were poems, but he also wrote a major prose volume, Kitab al-Fawa'id fi Usul al-Bahr wal-Qawa'id detailing navigational practices in the Indian Ocean. A later Arabic source claimed that Ibn Majid showed Vasco da Gama the way to India, but the journal of Vasco da Gama's voyage, written by an eyewitness, states that the navigator who showed the Portuguese to India was a Gujarati Indian, not an Arab .In addition, other historians have shown conclusively that Ibn Majid would have been too old to have still been navigating when da Gama arrived in 1498 . Another navigator, Sulayman al‐Mahri from al‐Shihr, Yemen, wrote five navigational treatises in the sixteenth century, all in prose . Although it has been claimed that he was Ibn Majid's student, there is no evidence that he ever studied directly with him. The third navigational author is Sidi `Ali Raʾis, a Turkish admiral who sailed a portion of the Indian Ocean and wrote a navigational manual in Turkish in 1553 entitled al-Muhit (the Ocean) .
What is immediately apparent in the works of these authors is the strong reliance on celestial navigation, particularly stars, for navigating at sea. One of the essential skills of Indian Ocean navigation was measuring the height of stars to determine one's latitude. This is due to the fact that the majority of the northern Indian Ocean trade routes were within 25° of latitude to the equator. This meant that the Pole Star and other circumpolar stars were relatively close to the horizon and could therefore be accurately measured as indicators of latitude. This became the foundation for determining one's position at sea. Navigators measured the height of stars not in degrees, but in fingers, based on the practice of extending one's hand and aligning the lower edge of the little finger with the horizon, and then counting the number of fingers from the horizon to the star . The Pole Star (Polaris) was the main star relied upon for this practice. The more fingers it measured, the higher it was in the sky, and the farther north one was. On the other hand, fewer fingers meant that one was farther south. For example, at the eastern tip of the Arabian Peninsula, Ra's al‐Hadd, with a latitude of 22.5° N, the Pole Star was eleven fingers high. However, in Cochin in southern India, at approximately 10° N, the Pole Star was only three fingers above the horizon . Although the Pole Star was important, it was not always visible, so a host of other stars, usually in pairs, were used to extrapolate the height of the Pole Star when it could not be seen. Ibn Majid mentions over 73 different star combinations that could be used for star‐altitude measurements . By the fifteenth century, star altitudes were measured not by hand, but with wooden instruments, simply called a “wood” (khashaba or hataba), replicating the function of the hands in order to create a greater degree of standardization. There are previous historical references to stars being measured to determine latitude, and even Marco Polo mentions the location of Gujarat in terms of the height of the Pole Star . But the works of Ibn Majid and al‐Mahri provide considerably more detail regarding the specific methods and measurements.
There is also evidence for the use of other navigational instruments. Although the Chinese had been using the compass since approximately the fourth century BCE, the first reference to the maritime use of a compass (composed of a metal fish floating in water and magnetized with a lodestone) in an Islamic context is in the thirteenth century Muslim mariners adapted this Chinese technology and integrated it with their pre‐existing system of stellar rhumbs, using the names of the stellar rhumbs on their compasses. Thus, “northeast” on the compass was not known as “northeast,” but rather “the rising of Capella” (matla' al-ʿAyyūq), and “northwest” as “the setting of Capella” (mugh-ib al-ʿAyyūq). They also refer to sounding leads and navigational guides. Although neither charts nor quadrants are mentioned in the Arabic navigational literature, Portuguese sources state that Indian Ocean navigators used them in the late fifteenth and sixteenth centuries .
Indian Ocean navigators also developed a series of set routes, with detailed descriptions outlining dates of departure, bearings, potential hazards, and markers for changing course while heading from one port to another.
For example, there were set routes to travel from Aden to Hormuz, or from Muscat to Malacca. Al-Mahri is particularly detailed in this regard, providing over 30 set routes in his work, al-'Umdat al-Mahriyya ). In spite of the previous historiography on the subject, the Portuguese entrance into the Indian Ocean seems to have had relatively little impact on navigational practices in the short term. Rather, the Portuguese appear to have adopted many of the practices of Indian Ocean navigators, and the Portuguese relied heavily on local navigators and sailors to man their ships. However, over the long term, developments in eighteenth-century European navigation, such as the evolution of the sextant and the chronometer, began to seep into local use, and by the modern period (1800-present), Indian Ocean navigation had obvious European influences that coexisted with older regional practices .
4 | THE LITERATURE
Considering its geographical breadth, the quantity of extant manuscripts, and the importance of the topic, it is not surprising that there is an established historiography in Arabic and European languages on Indian Ocean navigation. The initial Orientalist forays into the subject began with Sidi Ra'is' Turkish text, al-Muhit. Austrian Orientalist Baron Joseph von Hammer-Purgstall first translated this work, in segments, in a journal series between 1834 and 1839. The translation, however, was problematic due to the difficult and obscure nature of the technical vocabulary involved. Other European scholars soon inquired further. In 1836, James Prinsep, intrigued by von Hammer Purgstall's translation, provided a description of a Maldivian mariner using a navigational instrument he referred to as a kamâl—a description that has since become the de facto representation for star-altitude measuring instruments in the Indian Ocean. Captain Congreve recorded similar navigational practices used by mariners of the Cormandel coast in 1850, and Bittner and Tomaschek provided a topographical survey in German of the geography found in al-Muhit, as well as a re-translation of select passages in 1897.
However, as mentioned above, it was the discovery of Ahmad b. Majid's and Sulayman al-Mahri's manuscripts in France in the beginning of the twentieth century that transformed scholars' understanding of Indian Ocean navigation. Published as facsimile copies by Gerard Ferrand in Instructions Nautiques et Routiers Arabes et Portugais des XVe et XVIe Siecles), these texts provided a wealth of primary source material in Arabic that predated the Turkish al-Muhit, and which indicated that, in fact, al-Muhit borrowed heavily—and perhaps copied directly—from the Arabic texts, and those of al-Mahri in particular. Although Ferrand intended to produce translations of the manuscripts, they were never published.
After this initial fervor of activity in the first part of the twentieth century, academic interest in these texts then diminished somewhat for almost a half century. The main exception came in 1957 when the Russian scholar Teodor A. Shumovsky published a manuscript copy and Russian translation of what has been proven to be a corrupted version of one of Ibn Majid's poems, al-Sufaliyya, which relates to navigation along the East African coast. In 1960, the poem was translated into Portuguese due to the supposed connection between Ibn Majid and Vasco da Gama.
Rather, the focus shifted to other maritime-related texts and subjects. Jean Sauvaget translated an edition of The Accounts of China and India into French in 1948, which is the first account in Arabic of the route to and from the Arabian Gulf to China in the ninth century. George Hourani in his seminal work, Arab Seafaring, first published in 1951 , provided an excellent short general introduction of the contours of pre-modern navigation in Indian Ocean, relying in a variety of Arabic geographies and texts, including that of Ibn Majid. A decade later, the French historian Auguste Toussaint, influenced by the Annales school, wrote Histoire de l'Océan Indien in 1961, one of the first oceanic histories of the Indian Ocean. Surprisingly, although he refers to the Arabic and Chinese geographies and was aware of the work of Ferrand, he does not discuss either Ibn Majid or Sulayman al-Mahri in any depth.
In the 1970s, there was a revived interest in the serious study of the fifteenth- and sixteenth-century navigational texts again. Two of the main scholars to study Arab navigation, G. R. Tibbetts and Ibrahim Khoury, almost contemporaneously published the two most important modern works on Arab navigation. Khoury published an extensively edited four-volume critical edition of the works of Ibn Majid and al-Mahri in 1970-1972 in Arabic , which relied on other subsequently discovered manuscript copies as well as those from France. Tibbetts published his influential treatise on Arab navigation, Arab Navigation in the Indian Ocean Before the Coming of the Portuguese in 1971 (republished in 1981), which included a translation of Ibn Majid's longest and only prose work, Kitab al-Fawa'id. Tibbetts' work has since become so influential in English-language academic discourse that it is practically the sole lens for non-Arab historians into the world of Indian Ocean navigation. This is in large part becauseTibbetts provides the most detailed inquiry into Indian Ocean navigation in English to date. Although he deserves considerable respect for his contribution, his translation has been criticized by Arab scholars in the field (Ibn Majid, 2004). Meanwhile, Khoury's four-volume Arabic publication, with a more balanced treatment of al-Mahri and an extensive and detailed glossary, has unfortunately been ignored.
After Tibbetts, the study of the science of Indian Ocean navigation waned again in western academic circles, with only the odd chapter or article devoted to the subject. K. N. Chaudhuri provided a summary of the general parameters of navigational practices in his foundational work on the Indian Ocean, Trade and Civilization in the Indian Ocean, but primarily relied on the work of Tibbetts and Ferrand for his discussion. Tolmacheva wrote two articles related to the topic, one on the stellar compass rose, (1980) and another on a previously unknown manuscript of explored the astronomical accuracy of a variety of star-altitude measurements described in Tibbetts' translation from a mathematical perspective.
Meanwhile, Arab scholars quietly continued to produce relevant work. Khoury subsequently published translations of Ibn Majid's poems (Ibn Majid, 1983, 2010), but due to their inadequate distribution and poor English, the majority of historians of the Indian Ocean have not reviewed these volumes. The Yemeni maritime historian Hassan Salih Shihab edited a previously unknown manuscript of Ibn Majid's poems found in Omani archives and wrote secondary summaries of navigational principles, as well as a lexicon, all of which have also received little attention.
In the twenty-first century, with the growth of the field of Indian Ocean studies, many of the Indian Ocean related monographs periodically address the topic of navigation. The general surveys of the Indian Ocean such as those by Pearson and Alpers both discussed navigation in their works. The best survey study to date has been that by Abdul Sheriff, who in one chapter in Dhow Cultures of the Indian Ocean, provides the most indepth and nuanced summary of Indian Ocean navigation. There have also been shorter surveys of Indian Ocean navigation included in other works related to more specifically maritime topics. Dionisius Agius has addressed the topic of navigation in his trilogy on maritime activity in the Islamic world also see Tolmacheva,, and Fuat Sezgin ) also provides a description of the main principles, with a particular focus on navigational instrumentation. Most of these surveys heavily rely on Kitab al-Fawa'id for their understanding of Indian Ocean navigation. An edited volume, The Principles of Arab Navigation, published in 2013, attempted to diversify the discussion of the topic away from Ibn Majid by addressing topics such as elements of al-Mahri's work, navigational experiments at sea, and Arab navigation since 1850.
However, with only a handful of publications of original work produced in the past century, and with the main authoritative source having been written over 45 years ago, it is evident that the historiography of Indian Ocean navigation is currently in a relatively stagnant state. This is particularly troubling because many of the most prominent scholars in the field such as Ibrahim Khoury, Hassan Salih Shihab, and G. R. Tibbetts have all passed away, and a new generation has yet to take their place.
A deeper examination and translation of the available primary source literature, particularly the Arabic corpus of Ibn Majid and al‐Mahri;
- A renewed effort to cross‐contextualize these texts to provide a more culturally pluralistic understanding of western Indian Ocean navigation; and
- The creation of alternative theoretical frameworks for better conceptualizing this body of knowledge.
First, there needs to be a closer examination of all available navigational texts and manuscripts by Ibn Majid and al‐Mahri, as well as other works on the subject in Arabic. Although Tibbetts' translation of Kitab al-Fawaʾid is justifiably regarded as the definitive work on the subject in English, and no other volume provides a comparably exhaustive discussion of the principles and geography referred to in the Arabic text, it has nevertheless been criticized by Arabic scholars. Consequently, the continuing reliance on Tibbetts' work by western academics is unquestionably problematic, particularly when there are so many other texts readily available in both print and manuscript form. Ibn Majid's collection of poems, for example, has been almost completely neglected for the last 30 years. These poems provide a wealth of additional knowledge on navigation at the time, elaborating on previously unknown regions and practices. For example, Ibn Majid writes almost nothing regarding the navigation of the Arabian Gulf in Kitab al-Fawaʾid, in spite of claims to his being born in Julfar. However, one of his poems, which has not been studied in any depth, is devoted to navigation in the Gulf. An in‐depth analysis and translation of this poem would add significantly to our understanding of navigational practices in the Gulf, where the wind patterns are significantly different from those in the rest of the Indian Ocean. Additionally, navigational techniques in the Gulf are less reliant on star‐altitude measurements because the region's northerly latitude means that the Pole Star is higher in the night sky. Furthermore, these poetic treatises represent an important oral tradition of navigational knowledge in the pre‐modern Arabic milieu that is not adequately represented in Kitab al-Fawaʾid, and which can also be compared with more modern Arabic navigational poems found in the ethnographic record .
Even more importantly, no critical, comprehensive translations of Sulayman al‐Mahri's work exist (of which I am aware)—despite the fact that they deserve such attention. On the contrary, Sulayman al‐Mahri is often ignored or incorrectly portrayed merely as Ibn Majid's student in the secondary literature on the subject. However, it was al‐ Mahri's work, rather than Ibn Majid's, that the Turkish admiral Sidi Ali Ra'is primarily relied on when he composed his treatise in 1553. Al‐Mahri's work has important technical distinctions from that of Ibn Majid, with a greater emphasis on distance calculations and set routes, and less focus on star‐altitude measurements. These differences have yet to be adequately analyzed. Were they due to dissimilarities in personality, or, given that Sulayman al‐Mahri wrote almost two decades after Ibn Majid wrote Kitab al-Fawa ʾid, do they represent important changes over time in navigational practices?
Al‐Mahri's texts also provide additional detail and texture to our knowledge of navigation in this time period. For example, in his volume Sharh al-Tuhfa, a work that Tibbetts dismisses as largely “unnecessary,” al‐Mahri describes the best type of lodestone for magnetizing the needle in a mariners' compass. His description mentions that the lodestone will not work if exposed to the odor of either garlic or onions, but that its magnetic properties will be revived if one soaks it in vinegar or the fresh blood of a male goat . This fascinating intertwining of regional folk beliefs and a “scientific” instrument that was originally invented by the Chinese and modified by Arab navigators is just one of the many details not mentioned in Kitab al-Fawaʾid.
Thus, the heavy reliance on Ibn Majid's Kitab al-Fawaʾid creates a relatively static and myopic vision of “Arab” navigation, in large part because it is a single work, representing one person's vision of a large body of knowledge in a certain time and place. Consequently, focusing greater attention on other texts, such as the works of al‐Mahri, could provide a more diverse and dynamic picture of Arab navigational knowledge, practices, and technology.
The first steps to remedy this situation are to create authoritative bilingual critical translations of both Ibn Majid's poems and Sulayman al‐Mahri's navigational guides, in order to provide more detailed and comprehensive primary source material for non‐Arabists to examine. These translations will have a broader relevance to the fields of both Indian Ocean studies and the history of science and would certainly create a more nuanced picture of navigation at the time. Further study and translation of these texts will allow historians to ask different types of questions than those posed by Ferrand and Tibbetts over a half‐century ago and will, at the same time, provide an abundance of material with which to answer these questions.
Second, these Arabic manuscripts need to be properly contextualized within the larger cultural framework of the Indian Ocean. The chronological and linguistic biases of the surviving literary sources have profoundly limited our understanding of navigation in the Indian Ocean. One of the most important aspects of the discovery of the Arabic navigational manuscripts, as valuable as they are, has been to create an overly Arab‐centric narrative. Almost all of the English language publications use the phrase “Arab Navigation” in the title, and attempts to diversify the narrative have been relatively limited. The most successful attempt to date has been Abdul Sheriff's chapter on navigation in his work Dhow Cultures of the Indian Ocean (2010), but much more work needs to be done in this regard. Navigation has often been conceptualized as a culturally contained intellectual “tradition,” limited to one particular ethnicity, language or civilization. However, historical evidence indicates that maritime societies, in particular those participating in long‐distance seafaring, were much more culturally interactive and diverse than settled land‐based agricultural environments.
With such culturally pluralistic seascapes, it is no surprise that Arabic texts contain references to a much more culturally diverse set of practices. The texts have a deep foundation in Arab and Bedouin star lore and poetic traditions, and yet they also incorporate Ptolemaic conceptions of constellations. Their system for marking the correct time to measure the stars relied on the lunar mansion system (al-manazil), which was a shared tradition found in Chinese, Indian, and Perso‐Arabic astronomical traditions. Al‐Mahri is particularly interesting in this regard. Within his relatively short treatise on calendar conversion calculations, called Qiladat al-Shumus, he refers to the Coptic, Byzantine, Persian Nayruzi, and lunar Arabic calendars, reflecting the diverse culturally constructed systems of time calculation that Indian Ocean navigators had to negotiate with in order to be proficient in their craft. Al‐Mahri also acknowledges that the Cholas navigators of southern India made star‐altitude measurements that were more accurate in certain locations than those used by al‐Mahri. An in‐depth examination of the textual sources is required to further explore the complex cultural strands embedded in the Arabic literature and understand the degree to which they interacted with other cultural navigational practices.
This cultural plurality also exists in other navigational linguistic contexts. Ashok Rajeshirke has recently published a collection of Gujarati navigational manuals from the early modern period that illustrate the profound influence different cultural strands had on Gujarati navigation at the time. Although written in Gujarati, many were composed or revised in Muscat, Oman, and contain evidence of considerable cultural cross‐pollination. They relied on the Arabic stellar compass for rhumbs, and Arabic names for the planets, as well as sun declination charts from the Portuguese. They had a 365‐day sailing calendar similar to the Persian Nayruzi calendar used by Arab navigators, but referred to it locally as the dariyai, and even converted it into Gregorian dates as well for more on Gujarati navigation also see Arunachalam, Machado, and Simpson, . In addition, Hyunhee Park has recently explored the cross‐cultural connections in cartography between the Islamic and Chinese world. Further work of this nature will provide a more balanced perspective of Indian Ocean navigation that acknowledges the important role that Arab navigators had, while also emphasizing the intercultural elements of navigation.
This brings us to the third point, which is that much more work needs to be done to construct a meaningful theoretical framework for understanding navigation in the Indian Ocean. There is a tendency in navigational history to view navigation through culturally limiting lenses. Thus, there is discussion of “European” navigation, as opposed to “Arabic” or “Polynesian” navigation, all of which are assumed to be conceptually self‐contained, with only a few cross‐cultural exceptions. This in turn allows scholars to view European navigation, particularly in the early modern period, as “scientific,” privileging their knowledge with an aura of intellectual authority that is not often applied in other cultures. Navigation practiced in other cultural contexts, such as the Pacific or the Indian Ocean, are instead referred to as a “tradition,” an “art,” or a “craft.” Previous work on Indian Ocean navigation has not delved into how to best theoretically articulate “Indian Ocean navigation” as a meaningful category. Is it a series of relatively self‐contained and static cultural traditions that occasionally overlap in periods of a particular historical conjuncture, such as the arrival of the Portuguese in 1498 ? Or is it a dynamic and interactive series of practices used by maritime actors across multiple cultural contexts? Considering the level of sophistication that exists in other fields relating to the history of science, the field of the history of navigation in the Indian Ocean requires a much more rigorous theoretical discussion in this regard.
5 | CONCLUSION
Considering its barely touched textual corpus and the opportunity for further cross-cultural research, the study of Indian Ocean navigation has tremendous potential to add technical and theoretical depth to the growing discipline of Indian Ocean studies, and enrich recent efforts to create a more globally inclusive narrative of the history of science. As a body of knowledge, Indian Ocean navigation for millennia has facilitated maritime migrations, enabled maritime commerce, and fostered the interaction and spread of cultures and religion across the Afro-Asian littoral. In other words, it is a significant field of historical study and deserves more collective attention than it has hitherto received.
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