In the sixth century, two events took place on the Arabian peninsula. One brought down an ancient commercial empire. The other led, years later, to a spiritual empire that would eventually reach and re-shape much of the known world.
The most important of those events was the birth of the prophet Muhammad in Mecca. By the time he died in 632, the message of Islam that had been revealed to him had united all Arabia under one rule for the first time and less than 100 years later the new Empire of Islam reached from the borders of France all the way to China.
The other event was far more prosaic: the collapse of a dam in Yemen in the Peninsula's south-west corner. Why it collapsed has been debated by scholars for years, some saying it was caused by exceptional rains, others believing it was caused by an earthquake. But whatever the cause, the collapse of the dam marked the end of an ancient civilization of South Arabia - a civilization centered on the fortified city called Marib and on its dam.
In earlier centuries this civilization - called Saba in Arabic and Sheba in the west - was exceptionally wealthy. According to the Koran Saba's queen, known in the west as the Queen of Sheba, ruled from "a magnificent throne." According to the Bible she also visited King Solomon in Jerusalem about 900 B.C. arriving, says the First Book of Kings, "with a very great train with camels that bare spices, and very much gold, and precious stones..."
Saba's riches came from its role as a trans-shipment point for Eastern luxury goods being traded to the West and from the collection and sale of two rare and expensive aromatic resins - frankincense and myrrh - for which the ancient world had a nearly insatiable appetite. They were used by the ancient Egyptians in embalming, were burned as offerings to the pagan gods of East and West, were valued as medicines from first-century Rome to 11th-century Persia, and perfumed the state occasions of royal and imperial courts throughout the known world well into the early Middle Ages. Yet they grew, almost exclusively, in Southern Arabia - whose inhabitants told fabulous tales about the dangers and difficulties of collecting them in order to deter competitors - and were a vital factor in the prosperity that earned the area the name Arabia Felix - Happy Arabia.
The trees that produced frankincense and myrrh probably grew wild. Scholars simply aren't certain. But they must have been jealously tended, nevertheless, as were the other agricultural crops that provided the broad base of the Sabaean economy - as well as the dam that made agriculture possible.
Sabaean agriculture, in fact, was based on more than just the dam. In addition, those ancient hydrologists had developed a water management system that included numerous wells and an extensive irrigation network. But the centerpiece of the system was the Marib Dam - Sudd Marib - an engineering marvel of the age.
Faced with meticulously cut stone blocks, the dam spanned an 1,800-foot gap cut through the Balaq Hills by the Wadi Adhanah, and rose 15 feet above the watercourse, according to modem estimates. Awed ancient writers gave greater dimensions - 100 feet high and over 5,000 feet long - but they apparently confused the dam proper with its extensive associated irrigation system.
This branched out from two massive stone and mortar abutments at the dam's north and south ends - they still stand today - that were connected to the sides of the Balaq Canyon by 25-foot thick walls. From the abutments, water was distributed to the extensive cultivated areas along the downstream banks of the wadi by a system of branching canals - the main one on the northern end more than a mile long -equipped with gates and sluices.
According to inscriptions, the dam was built in the seventh century B.C. by a ruler named Sumhu' Alay Yanuf and his son Yatha'-Amar Bayyin, but it was maintained, for centuries after, by successive generations of skilled Sabaeans and, later, by the kings of Himyar, a civilization that succeeded the Sabaeans as a potent force in South Arabia.
Their people, apparently, were a handsome race of medium height, with fair skin and short, straight noses. They lived in many-storied houses, viewing the passing caravans through window-panes of alabaster sliced so thin, according to one account, that those within a house could distinguish the shapes of birds flying overhead.
If agriculture was the base of Sabaean prosperity, however, international trade was the chief source of its wealth. By providing trans-shipment of silks from China, produce from East Africa and treasures from India - cinnamon and pepper, gold and precious stones - the Sabaeans, and other South Arabian peoples, dominated trade between the civilizations of the East and those of the Mediterranean. Clearly, much of this trade was in luxury goods, but ordinary goods were traded too. In A.D. 60, a traveller listed these products as available in the market place of Saba's chief port: purple cloth, clothing - plain, embroidered or interwoven with gold - saffron, sweet rush, muslin, cloaks, blankets, sashes, fragrant ointments, wine and wheat.
To all this were added aromatics, products so valuable that all Rome was scandalized when Nero burned the whole annual frankincense production of Arabia to mark the funeral of his wife Poppaea. As the Roman historian, Pliny, put it, "It is the luxury that is displayed by man, even in the paraphernalia of death, that has rendered Arabia 'The Happy.'"
The Himyarites, of course, still possessed the fertile agricultural areas and the frankincense and myrrh trees that produced the most valuable cash crops of South Arabia. But soon even they lost their marketability, thanks - ironically - to the spread of Christianity, which, for a time, discouraged the use of frankincense along with other pagan patterns of worship. Trade, therefore, fell off and with it the region's ancient and famous prosperity.
Himyarite knowledge of hydraulic engineering apparently also declined. Sabaeans, in their great days, had dealt with the problem of controlling and conserving water by sophisticated methods and for a period the Himyarites kept this knowledge alive. But now these techniques were forgotten, and maintenance of the dam became increasingly difficult. The dam broke and was repaired in AD. 450 and again in 542, but in the latter part of the sixth century - AD. 570 according to early Muslim historians - the dam broke for the third and last time, the skill, and perhaps the will, to repair it having vanished.
Subsequently, as a result, many farmers of Marib began to migrate - some in whole tribes north to Syria, as their descendants relate to this day - while others joined the victorious armies of Islam and scattered to the four corners of the earth. The Koran itself refers to the collapse of the Marib Dam as a punishment on the Sabaeans for their ungratefulness to God.
Without the dam to distribute rainfall through Marib, the water tended to run off into the deserts nearby and disappear. Trees, vegetables and grains grew no more and, inevitably the sands moved in. Today, Marib grows no more than a little wheat and, during the rainy season, some sorghum, sesame and a kind of alfalfa fed to animals. The people whose ancestors once fed a large part of the Middle East now import much of their food, and the town of Marib is largely in ruins.
The story, however, may yet have a happy ending - thanks to an Arab leader who proudly traces his ancestry back to the Marib area: Shaikh Zaid Bin Sultan Al Nuhayam, President of the United Arab Emirates. Determined to revive the ancient fertility of the area, Shaikh Zaid, with the financial backing of the U.A.E., has launched a major restoration project to find water and expand croplands.
The project, in fact, is already well underway. A Swiss study team, for example, has been taking soil samples and studying aerial photographs in preparation for an extensive well drilling program scheduled to begin in 1978 and Robert Law, a golden-bearded Scotsman who is the team's head, is already sure the program will be a success. "Water is sometimes as close as a few meters underground in a gorge in the dry season, but in most of the area I think it is between 50 and 130 feet down." This is the depth of the hand-dug Himyarite wells, dating to the sixth century A.D., from which most of Marib's present-day residents still draw their water by hand.
Law's soil samples went back to England for analysis last year, and his team is now studying the aerial photographs, painstakingly marked out to show land ownership. Determination of boundaries has its difficulties, however, since they are measured in traditional units that vary widely from one area to another. They tentatively plan nonetheless, to drill about one well for every 10 farms - and then to ask the beneficiaries to pay a modest amount for it to make the project self-supporting. "We know that it is going to meet universal resistance," says Law. "People feel that water is like air or sunlight: it belongs to everyone, so why should they have to pay for it?"
Farmers in the Marib area still have the ancient skill of making a small amount of water irrigate an astonishingly large area of land, channeling it through a radiating pattern of shallow ditches. Furthermore, Marib's soil almost certainly has an ample natural supply of nitrogen, and plants growing in it develop formidable stems and root systems. The cosmos of western gardens, for example, is a rather flaccid flower. In Yemen, given half a chance, it rises up on half-inch stems - perhaps a good omen for new productivity in Marib.
The famous Marib dam, however, will not be rebuilt. Because of its history its value as an archeological site and historical monument far outweighs its agricultural potential. Even so, some of the prosperity that it provided so long ago may soon return, with the new water, to the land once called Saba.
Rhea Talley Stewart, author of Fire in Afghanistan, is a member of the Asia Society's Afghanistan Council. A journalist all her life, she is now writing a thriller.