The fate of the Iberian Peninsula took a radical turn in 711 when Muslim forces crossed the straits of Gibraltar and quickly overcame Visigothic opposition. By 714, they controlled almost all the peninsula; the land they occupied they called al-Andalus.
In the roughly two centuries (500-700) the Visigoths ruled, they had been largely indifferent to exploiting the land or to developing trade and commerce, unlike the Romans who had preceded them. For the Romans, Hispania was a mineral and agriculture storehouse, and like the Romans, the Moors too exploited and cultivated the land with great skill and converted it into one of the wealthiest countries of the Mediterranean.
The economic prosperity of al-Andalus was the product of a healthy combination of commerce, agriculture and industry. We know from the Phoenicians, Greeks, Carthaginians, and Romans that trans Mediterranean commerce was a long established activity. When Islam rooted itself from the Middle East along the North African coast to Spain, it changed only the ideological colour of those countries, not the fundamental pattern of economic life. If anything, Muslim thinking from the beginning had encouraged trade and mobility; after all, the Prophet himself had been a merchant and the Qur'an enjoined Muslims to travel and see the wonders of Allah’s creation. And in Arabic, al-Andalus had a common language with all of North Africa and into the Middle East, which facilitated commerce.
Initially al-Andalus would have imported much of what it required, commercially and agriculturally. Then, as its own manufacturing ability improved it began to participate fully, exporting wrought iron, glass, ceramics (the famous azulejo tiles that are still manufactured) paper goods, woollen textiles. Cordoban leatherwork was highly prized (it still is, although tourists are often palmed off with more brass studs than leather in their boxes) as were the fine silks dyed in brilliant colours. These manufactured goods, together with metals and minerals (e.g. iron, copper, mercury) found ready market around the Mediterranean as well as within the peninsula itself. In return al-Andalus imported goods not easily accessible at home: e.g. gold and ivory from south of the Sahara. The gold --from the Upper Niger area, known then as Sudan-- became the basis of exchange in Europe until the discovery of America.
Supporting the manufacturing sector was an agricultural infrastructure that made al-Andalus the envy of the Mediterranean. At a time when agriculture in the rest of Europe was just a matter of manual labour, in al-Andalus it was treated as a science. In the 12th century, for example, Abu Zacaria published a Book of Agriculture in which he discusses irrigation, the qualities of edible plants and vegetables, the use of fertilizers, the relationship of animals to the land, the diseases that affected animals, fowl, bees etc., and how to cure them. The cultivation of beautiful gardens started early, with Abd al-Rahman I (r. 756-85), and culminates with the 14th century Generalife gardens in the Alhambra Palace of Granada.
The vital cog that made possible the blooming of al-Andalus was irrigation, feeding the gardens and converting arid areas into green oases. The Moors did not introduce irrigation to the peninsula, but what they did do was improve and expand significantly on what the Romans had started. Roman irrigation had been primarily based on gravity which limited the amount of land that could be irrigated. The Moors were accomplished practitioners of the water mill (aceña) and the water-wheel (noria) which could raise water and so expand the terrain available for cultivation. Dotted around the landscape of southern Spain, we can still see these Moorish water-wheels, their buckets extracting water from a lower level to deposit into channels along which it is then carried to the outer fields. The irrigation legacy of the Moors can still be seen today in practice in the highly irrigated areas around Valencia and Murcia, where they are known simply as the La huerta .
The huerta of Valencia is particularly noted for its rice, but rice was just one of the many new products that enriched life for the inhabitants of al-Andalus. Staples such as corn, olive oil, grapes, beans, lentils and chickpeas were long established but a wide variety of new goods introduced by the Moors included fruits (oranges, lemons, limes, watermelons, figs, pomegranates, almonds, bananas, mangos, apricots, grapefruit), vegetables (artichokes, eggplants/aubergines, spinach, carrot, parsnip), spices (cinnamon, cloves, nutmeg, cumin, caraway, coriander) and herbs (fennel, mint, parsley). And to these we could add cash crops such as sorghum (a strain of “dry” wheat) cotton, flax, sugar cane and silk.
In Valencia, the system of water distribution is still regulated by a body of eight “peasant” judges called the Tribunal of the Waters (Tribunal de las Aguas). Any farmer with a grievance can appeal to the Tribunal which meets every Thursday at noon under the Door of the Apostles of Valencia's cathedral. The Tribunal has met since at least the 10th century, but no minutes are kept, and all decisions are final. A similar body exists in Murcia, called the Council of the Wise (Consejo de los Buenos). Both are recognised by UNESCO as historically important in the cultural heritage of mankind.
The resistance to drought of some of these products -- e.g. sorghum, cotton-- allowed land that would normally be unproductive for lack of water to be cultivated for the first time. In addition, Muslim agricultural practices encouraged fields to be cultivated every year instead of every two years, as in antiquity.
Accompanied by improved irrigation and fertilisation, the land became much more productive increasing thereby the prosperity and well-being of the Andalusis. Cities grew thanks to the benefits of a sound economy. People ate a healthier and more varied diet, which in turn allowed for more leisure activities (e.g. to play chess, introduced into al-Andalus in the 10th century, or to create beautiful gardens as sources of aesthetic pleasure or meditation). By the 10th century, Córdoba had become the largest city in Europe, with a population of approximately 100.000. It was a sophisticated magnate attracting people from Europe and all corners of the Mediterranean. Culture flourished and learning was highly esteemed. Andalusis were recognised as leading scholars in algebra (an Arabic word), astronomy, medicine, botany, geography, history etc., fields which had a wide impact on European life in the Middle Ages.
The consumption of food was already an art by the 10th century. In the 9th century, Ali ibn Nafi, a famous Persian scholar exiled from the court of the Caliph of Baghdad, landed in Córdoba. Although renowned as musician, astronomer and geographer, Nafi --or Ziryab as he was better known-- is best remembered now as arbiter of good taste. A trendsetter in fashion and advocate of personal hygiene, Ziryab rejected food piled on one plate in favour of separate courses, beginning with soup, then hors d'oeuvres, followed by fish, meat and desserts of fruit, nuts or compote. Out went heavy gold or silver goblets for drink, to be replaced by delicate glassware. To ensure this, he saw to it that a glass factory was established in Córdoba, the fame of which soon spread far and wide.
We can give the last word regarding the wealth of al-Andalus to the 10th century Jewish scholar, diplomat and physician to abd al-Rahman III, Hasdai ibn Shaprut, who remarked enthusiastically:
The land is rich, abounding in rivers, springs, aqueducts; a land of corn, oil and wine, of fruits and all manner of delicacies; it has pleasure gardens and orchards, fruitful trees of every kind, including the leaves of the trees upon which the silkworm feeds.... There are also found among us mountains ... with veins of sulphur, porphyry, marble and crystal. Merchants congregate in it and traffickers from the ends of the earth ... bringing spices, precious stones, splendid wares for kings and princes.... (Gerber 31).
Barton, Simon A History of Spain Basingstoke, Hampshire 2004
Collins, Roger Early Medieval Spain: Unity in Diversity 400-1000 Basingstoke, Hampshire 2nd. Ed. 1995
Fletcher, Richard Moorish Spain London 1994
______________ The Quest for El Cid London 1989
Gerber, Jane S The Jews of Spain: A History of the Sephardic Experience New York 1992
Postan, Michael M The Cambridge Economic History of Europe: The Agrarian Life of the Middle Ages Cambridge 2nd. ed. 1966 (1st ed. 1941)
Reilly, Bernard The Contest of Christian and Muslim Spain 1031-1157 Oxford 1995
For a short history of th Tribunal of the Waters, see: http://www.typicallyspanish.com/news/publish/article_32930.shtml
For an informative page on norias, see: http://www.yachtmollymawk.com/2008/11/spanish-water-works/