In 1492, when Christopher Columbus set off from Spain to find a westward route to Asia, he was looking to secure Europe's kitchen, not change it. Europeans had used black pepper as a medicinal aid and to spice up their cooking since Greek and Roman times. The ingredient, imported from the Spice Islands of Asia, had fueled the economies of trading ports like Alexandria, Genoa and Venice. But by the Middle Ages, black pepper had become a luxury item, so expensive that it was sold by the corn and used to pay rent and taxes. When the traditional land and sea routes to Asia were cut off by the rise of the Ottoman Empire, European traders looked for new ways to India and the lands beyond  not just for pepper but for other lucrative spices, and for silks and opium. Columbus headed west, certain he would find a new route to the East Indies. He never got there, of course, but in the islands of the New World the Italian navigator found a fiery pod that would, within years, not only infuse southern European cooking with bold new flavors but also revolutionize cooking in India, China and Thailand, the very places he'd set out to reach.

The remarkable spread of the chili (or chilli, or chile, or chile pepper, to use just a few of its myriad names and spellings) is a piquant chapter in the story of globalization. Few other foods have been taken up by so many people in so many places so quickly. Ask a Chinese chili lover or an Indian or a Thai and most will swear that chilies are native to their homeland, so integral is the spice to their cooking, so deeply embedded is it in their culture. European and American chili addicts, though less numerous, are just as passionate about the spice.

In terms of keeping billions of people fed, the chili can hardly compare to rice or corn or even potatoes, of course. But by adding spice to such staples, by making even the poorest food rich in flavor, the chili has become one of the most important ingredients in the world. For hundreds of millions of poor, chilies are the one luxury they can afford every day, a small burst of flavor in the slums of Asia or the parched grazing land of West Africa. The secret to the chili's success lies in the fantastically colorful pods themselves: the chemicals that make them so hot and addictive. "Once we develop a taste for hot food, which provides a high, there is no going back," says renowned Indian cook Madhur Jaffrey. "It turns into a craving." The chili, she says, is not so much a seed of change "as a conqueror, or, better still, a master seducer."

Chilies are native to South America, where people have been cultivating and trading them for at least 6,000 years. Linda Perry, a postdoctoral fellow in archaeobiology at the Smithsonian Institution's National Museum of Natural History in Washington, has identified microfossils of the starch grains found in chilies on grinding stones and cooking pots unearthed in the Caribbean, Venezuela and the Andes. In a paper published in Science last February, she and fellow researchers found that domesticated chilies were being eaten in southern Ecuador some 6,250 years ago. Because there are no wild chilies in southern Ecuador, domesticated plants must have been brought there from elsewhere, perhaps from Peru or Bolivia where, according to Perry and other scientists, chilies were probably first grown by humans. "For whatever reason, a lot of people really liked them," Perry says. "Once they were domesticated, they spread very quickly around South America and into Central America."

Chilies belong to the genus Capsicum, a member of the nightshade family that includes tomatoes, potatoes and eggplants. Only five of Capsicum's 25 species have been cultivated, and in South America, where most of the world's wild chilies are still found, chilies' shapes and colors are far more varied than the classic curved red or green ones of Mexican cooking or the small bullet-shaped "bird's-eye" chilies used in Thai cooking, or the sweet green and orange bell peppers or capsicums found in a million salads. There are pea-shaped chilies, heart-shaped chilies, chilies with the bumps and nodes of a surrealist brain, and chilies that are flat and long like a bean. They come in purple, rusty red, yellow, black, bright orange and lime green. "There are thousands of types and we're still discovering new ones," says Paul Bosland, director of the Chile Pepper Institute at the New Mexico State University in Santa Fe. "The variations are incredible."

By the time Columbus sailed into the Caribbean in the late 15th century, chilies were a long-established part of most diets across the Americas. But as British author Lizzie Collingham relates in her excellent history Curry: A Tale of Cooks and Conquerors, which tells the story of India and its rulers through their food, Europeans initially weren't that enamored with the new spice that Columbus brought back from the New World. "On the Iberian peninsula," writes Collingham, "chilies were grown more as curious ornamental plants than as sources of a fiery flavoring." But if Europeans didn't immediately fall for the chili, they did become its greatest propagator. Portuguese traders carried it to settlements and nascent colonies in West Africa, in India and around East Asia. Within 30 years of Columbus' first journey, at least three different types of chili plants were growing in the Portuguese enclave of Goa, on India's west coast. The chilies, which probably came from Brazil via Lisbon, quickly spread through the subcontinent, where they were used instead of black pepper.

In Thailand, a short-lived Portuguese presence failed to convert the locals to Christianity but succeeded in revolutionizing the Thai kitchen. European traders introduced the spice to Japan. As chilies were added to the cooking pots of Asia, they also entered existing local trade routes and were taken to Indonesia, Tibet and China. The speed of their spread was phenomenal. Within a half-century of chilies arriving in Spain, they were being used across much of Asia, along the coast of West Africa, through the Maghreb countries of North Africa, in the Middle East, in Italy, in the Balkans and through Eastern Europe as far as present-day Georgia. Chilies spread so quickly in part because they are easy to grow in a wide range of climates and conditions, and therefore cheap and always available. "It was something spicy that now anybody could afford," says Bosland. "It was probably the very first plant that was globalized."

It wasn't the only new plant on the market, of course. Columbus returned from his journeys with baskets of strange vegetables and fruits including tomatoes, potatoes and corn. But nothing spread as fast as chilies. Bosland believes it was because people thought the red pods were a new type of black pepper. "People are very conservative when it comes to food," he says. "But here was something that they thought they knew, only it was spicier and easier to grow and get hold of." Tomatoes and potatoes took much longer to spread through Europe and Asia.

In recent years, chilies have returned to Europe from Asia on the menus of Indian and Thai restaurants. Indian food is now the most popular cuisine in Britain. In 2001 then Foreign Minister Robin Cook called chicken tikka masala  a British invention that mixes chicken, cream and tomato puree with chili and other spices  the country's national dish. In the U.S.  where, of course, the chili had arrived thousands of years ago from further south  Mexican food is ever more popular; salsas and chili sauces have outsold tomato-based ketchup since the early 1990s.

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