Tea (Camellia sinensis) - the most commonly consumed drink in the world after water - is an ancient beverage that was enjoyed for at least 1,600 years before Europeans ever tasted it (Chinese legend would have it almost 4,500 years). But it was only about 1,000 years ago, during the Song dynasty, that tea drinking started to become widespread and the government began to supervise the production of tea, regulate its trade, and collect tea taxes. Buddhist monks, who were not permitted alcohol and needed stimulation to stay awake during meditation, are given much credit for helping to popularize the beverage, as well as for carrying tea culture to Korea and Japan.

The Portuguese reached the South China coast in 1514 and became the first Europeans to gain the right to trade with China and the first to drink tea. They were also the first to introduce tea in Europe, and in the following century tea became one of the prizes sought in the three-way tug-of-war between the Portuguese, Dutch, and English for control of the China trade.

Tea - along with coffee and cacao - caught on in Europe during the seventeenth century, which in turn increased demand for slave-grown sugar to sweeten the new beverages. In London, "coffee-houses" that served these beverages began to multiply, and some - such as that owned by Edward Lloyd, which served a specialized clientele (in this case, individuals concerned with maritime shipping and marine insurance) - blossomed into other businesses like Lloyd's of London. Others, such as "Tom's Coffee House," opened by Thomas Twining, became major tea importers.

Tea was a staple of the English colonists in North America and, because of a British tax, became one more source of friction between the thirteen colonies and Parliament, which ultimately resulted in the Boston Tea Party - one in a succession of steps that seem to have led inexorably to the American Revolution.

It was only in the nineteenth century that Europeans discovered the secrets of tea cultivation, thus dispelling an ignorance that until then had meant monopoly for China. It was during the first half of that century that the British established the great plantations of Assam and Ceylon in India, and the Dutch created tea plantations in their East Indian colonies. But China nonetheless continued to dominate the markets of the world, and Britain continued to buy huge amounts of Chinese tea, even though, as a rule, the tea had to be paid for in specie.

The stubborn insistence by the Chinese that they needed nothing from the West but precious metals had always been a major irritant to the English, who now saw opium (grown in British India and smuggled into China) as a solution to the trade imbalance. The Chinese government became increasingly outraged at the wholesale addiction of its people, and its attempt to stop the traffic triggered the Opium Wars (1840-2), during which Britain triumphed militarily and effectively "opened" China to the trade of the world while wrangling huge territorial and trade concessions for itself.

The half century or so following the Opium Wars saw much competition in the China trade, and, with a Western public convinced that the fresher the tea the better, speed in transport became critical. For a few romantic decades, that speed was supplied by the famous clipper ships, which could rush tea from China to London or New York in 90 to 120 days instead of the earlier 6 to 9 months - effectively cutting the sailing time in half.

Tea reached the height of its popularity in the 1880s, but subsequent events served to sustain demand for the beverage. One was the introduction of iced tea to a thirsty crowd at the St. Louis World's Fair of 1904, which, although hardly constituting the invention of the drink (as has been claimed), certainly did help to popularize it. Another such event was the inadvertent invention of the "tea bag" by Thomas Sullivan in 1908. Sullivan was a tea merchant who began distributing his samples in hand-sewn silk bags rather than in tin boxes and was suddenly swamped with orders by customers who had discovered that they could brew the tea right in the bag.

It has been said that there are more kinds of tea in China than there are wines in France. To this is might be added that the classification of teas is every bit as complicated as that of wines. All tea starts as "green," and it must be rolled, withered, fired, and dried to deactivate an enzyme present in the leaves. If, however, the rolled and cut leaves are permitted to stand (and ferment) for one to three hours before heating, the tea becomes "black." If the leaves are semifermented, the tea is called "Oolong."

Tea grading is by leaf size. Young, soft shoots make the best tea, and thus only the bud and the top leaves are plucked from the bush. With black tea, the leaf bud is called "pekoe tip"; the youngest fully opened leaf is "orange pekoe"; the next leaf is "pekoe," then "pekoe souchong"; and finally there is "souchong" - the largest leaves that are used. The corresponding green tea grades are "twanky" for the bud, then "gunpowder," "imperial," "young hyson," and "hyson." The very small pieces, called "dust," generally go into tea bags.

The most famous of China's black teas is Keemun (or Keemum), known for its winelike quality. Darjeeling tea, from the foothills of the Himalayas, is one of India's contributions to the ranks of rare and prestigious black teas. Assam tea (from the same region but a lower elevation) is another. The Ceylon teas, from Sri Lanka, run the gamut - from the mild Flowery Orange Pekoe to the full-bodied Broken Orange Pekoe Fannings. The highest-grade Oolongs and the smoky Lapsung Souchongs come mostly from Taiwan.

In truth, however, most commercial teas are blends of several of these individual teas. Green teas are consumed mostly in Japan and some of the Arab countries, whereas black teas constitute the overwhelming bulk of the tea drunk in the West.