The Arabic term that denotes navigation is milaha, which signifies in a broader sense seafaring or in a narrower connotation the sailor’s act of determining the vessel’s position, location, and course to the destination. The sunna of the Prophet (his sayings and doings) and the Qur’an do not prohibit Muslims from sailing the seas. The Qur’an urges Muslims to consider navigating as well as exploiting the rich resources of the sea. Likewise, the sunna comprises hundreds of hadiths that exhort Muslims to organize maritime expeditions, to sail to Mecca on pilgrimage, to exploit marine resources, and to expand overseas trade. Regarding military operations at sea, Prophetic traditions give more credit to Muslim naval warriors and amphibious troops than to holy warriors who fight on land. One hadith says that ‘‘a maritime expedition is better than ten campaigns of conquest on land.’’ The Prophet also said that ‘‘a day at sea is equivalent to one month on land, and a martyr at sea is like two martyrs on land’’ and that ‘‘those who perish while fighting at sea will receive double the compensation of those fighting on land.’’ Al-Shaybani added that ‘‘any Muslim who takes part in a sea expedition would be doubly compensated (rewarded) and that once the soldier puts his foot on ship all his sins are forgiven as if he were born anew.’’ This emphasis on the double reward might reflect the legacy of a traditional fear of the sea and the necessity for encouraging recruitment for a religious war ( jihad) at sea. Maritime expeditions were regarded as very risky owing to unreliable weather and the naval power and maneuvers of the enemy, but these factors did not allow a soldier to flee the scene of the battle unless the Muslim admiral commanded his flotilla to withdraw collectively.
Although the Arabs had long been acquainted with the sea and had sailed for centuries through the Red Sea, the Persian Gulf, and the Indian Ocean using different types of ships and nautical techniques, it seems that they emerged as a global sea power after the Islamic military advents on the eastern and western fronts. Within less than a century of the emergence of Islam in Arabia, the Prophet’s followers dominated more than half of the maritime possessions of their former neighbors. The eastern, western, and southern shores of the Mediterranean Sea were entirely under Islamic dominion, as were the Red Sea, the Persian Gulf, and parts of the coast of the Indian Ocean. The Islamic expansions in the east and west united the former Persian and Byzantine territories that had been split by the successors of Alexander the Great (356–323 BCE). Owing to this new political unity, commercial activity between the Far East and the Mediterranean greatly expanded. As evidence, al-Biruni reports the following:
‘‘... the power of the Muslim state and its extension from the al-Andalus in the west to the outermost reaches of China and Central India in the east, and from Abyssinia and Bilad al-Zinj (East Africa) in the south to the Slav and Turkish land in the north enabled many nations to live together in intimacy, without allowing outsiders to bother them or to interrupt traffic. Other peoples who were non-Muslims and still pagans came to regard the Muslim state and its people with respect.’’ (Nazmi, Commercial Relations, p. 54)
Muslim caliphs, especially the Umayyads, maintained all dockyards and naval bases and the former administrative system of Rome and Byzantium in the southern shores of the Mediterranean as well as the marine system in the former Persian provinces; they also established new maritime installations. In AH 18/640 CE, when a severe famine spread in Arabia, Caliph ‘Umar ibn al-Khattab ordered a cleaning of Trajan’s canal, which connected Babylon with Clysma (sixty-nine miles in length), for the transport of sixty thousand irdabbs of corn from Egypt to Jar, the port of Medina. The real age of Islamic navigation began from the reign of ‘Uthman ibn ‘Affan. During the Umayyad and ‘Abbasid periods, many port cities on the Indian Ocean, the Persian Gulf, and the Arab, Red, and Mediterranean Seas flourished. Among these cities were Basra, Siraf, Aden, Suhar, Shihr, Qais, Bahrain, Hurmuz, Jedda, Jar, Qulzum, ‘Aydhab, Tarsus, Ladhiqiyya, Beirut, Sidon, Tyre (Sur), Acre, Alexandria, Rosetta, Damietta, Tinnis, Babylon, Barqa, and Tunis.
Over the course of time, Islamic societies contributed to the art of navigation. Their contributions are reflected in manuals of seafaring, nautical instruments, and the introduction of the lateen sail (a triangular sail suspended from a long yardarm at an angle to the mast) to Mediterranean navigation. Among the oldest Islamic manuals of navigational science that have come down to us are Kitab al-Fawa’id fi Usul ‘ilm al-Bahr wa-l-Qawa‘id, which was composed by Ahmad ibn Majid in 895/1490, and the works of Sulayman ibn Muhammad al-Mahri (d. 917/1511). This should not be interpreted to mean that Muslim navigators did not produce and use portolan charts (sing., qunbas) before the days of Ibn Majid. By contrast, Ibn Majid names two Persian navigators, Ahmad ibn Tabruya and Khawsshir Ibn Yusuf al-Ariki, who sailed during the early years of the eleventh century and who wrote navigational works. Another major instrument that Muslim astronomers and mathematicians developed as early as the seventh century was the astrolabe, an instrument for observing or showing the positions of the stars. On the astrolabe, latitude was determined by the height of the sun or the pole star, which was measured by the qis figure system (science of taking latitude measurements). A third nautical instrument that Muslim sailors transferred from China was the compass. This magnetic instrument was known to Muslim seafarers before the tenth century and probably was not considered very important in the East, because the skies over the Indian Ocean were usually very clear, especially during the times thatMuslimmariners sailed with monsoons. The earliest documented Arab use of the compass in the Mediterranean dates to the 1240s. In brief, Muslim navigators mastered astrology; the science of latitude and longitude; the nature and directions of winds; the seasons; the knowledge and locations of coasts, ports, islands, dangerous shoals, and the narrow maritime lanes; the use of various terrestrial instruments; and the art of calculating solar months and days. Most of the Islamic literature about the science of navigation was translated into Latin. For instance, the population of the Balearic Islands—especially the Mallorcan Jewish cartographers—played a vital role in translating Arabic nautical charts, instruments, and books into Latin. By doing so, Western European commercial ships could sail toward the Canary Islands and other destinations along western African coasts.
Islamic ships sailed to every part of the known world, including the major ports on the Mediterranean, Adriatic, Aegean, Marmara, Black, and Caspian Seas, in addition to the western African coasts on the Atlantic Ocean; their ships also sailed as far north as Denmark in 844. In the East, Muslim seafarers navigated the Red and Arab Seas, the Persian Gulf, and the Indian Ocean. Their merchant ships sailed from Near Eastern ports to India and Sri Lanka, Malay, the Philippines, Indonesia, and China in the Far East as well as Zanzibar, Mozambique, and even Madagascar in east and southeast Africa. Certainly the seasons and art of navigation differ for each one of the seas and oceans mentioned above. For instance, the sailing season in the Mediterranean had been observed from the Classical Hellenic period to the late medieval period. Ships habitually set out from the eastern basin of the Mediterranean during the early spring and returned from the west during the Feast of the Cross (‘id al-salib), which was celebrated on the 26th or 27th of September, whereas the return journey of ships heading eastward took place between the end of July and the beginning of September. However, sailing during inappropriate times was probably limited to military expeditions and instant transport of food supplies. As for the seasons of navigation in the Indian Ocean, navigators took advantage of the seasonal winds (monsoons) that blow in one direction for about six months and in the opposite direction for the rest of the year. With regard to the art of navigation on these waters, Muslim geographers (e.g., al- Mas‘udi [d. 346/956]; author of Muruj al-Dhahab) point out that navigating on each one of these seas required the previous personal knowledge and expertise of sailors.
The duration of maritime voyages depended on the seaworthiness of the vessel, the professional behavior of the sailors, the distances between ports of origin and destinations, cargo’s volume and weight, weather conditions, and the human hostilities that the ship could encounter. After the embarkation and debarkation ports were specified, captains and shipmasters could fix the ship’s course, whether it had to cross the high sea, hug the coast, or sail on inland waters (e.g., rivers, artificial canals).
This discussion cannot be concluded without saying a few words about navigation for military purposes. One of the few—but most important— sources about the subject that still survives is Al-Ahkam al-Mulukiyya fý Fann al-Qital fi l-Bahr wa-l-Dawabit al-Namusiyya, by Muhammad Ibn Mankali (d. 784/1382). His treatise, which contains explicit references to and fragments of an Arabic translation of Leo VI’s Tactica, is a mine of information about the technology of Islamic warships and ‘‘Greek fire’’; rights and duties of sailors, marines, and commanders; navigation under various climatic conditions; and, most importantly, how to plan, manage, and coordinate the battle at sea.