he Tang dynasty (A.D. 618 to 906) was unlike any other era in China, or in the world for that matter. It was a time of peace, prosperity and thriving international trade.

"The Tang Empire was very powerful and very rich," said Khalil Rizk, director of the Chinese Porcelain Company in Manhattan. "It had a mighty army." Its borders stretched from the Caspian Sea in the west to Korea in the east, and from Manchuria in the north to Vietnam.

Like Constantinople, the Tang capital city of Changan (the modern Xian) had two million inhabitants, about what it has today. The government supported a large class of Confucian literati who served as civil servants and ran the country well. The crime rate was at an all-time low, with prisons reportedly empty. Inflation was under control. The poor had enough rice to eat and the ability to pay taxes.

"It was one of the most sophisticated periods of Chinese history," said Theow H. Tow, Christie's international director of Chinese ceramics and works of art. "China attracted Persians, Indians and Jews. Last summer they found the site of a seventh-century Christian church, so there were already Christians there, too."

The silk route opened China to foreign ideas, religions, culture and lifestyles. Foreign merchants established markets in Changan to sell exotic spices and aromatics, camels, horses, tropical birds, jewelry, ivory and furs.

"The Chinese tended to be inward- looking," Mr. Tow said. "The Tang is one of the few dynasties that looked outward."

The first 137 years of the dynasty were also a golden age for Chinese art. "Nowhere else in the world were they making better pottery at the time," Mr. Rizk said. Tang potters made elegant earthenware vessels for everyday use and sculptures for tombs, including the Tang horses and camels so prized in the West.

The potters also created figurines representing exotic foreigners, with their odd physiognomy, costume and customs. "Sometimes the depictions of foreigners were like caricatures," Mr. Tow said. Horse grooms, for example, could have had wildly curly hair, bushy beards, big noses or bulging eyes.

Many of the Tang ceramics on the market today are tomb sculptures and vessels. The Chinese did not hedge their bets. They planned for the afterlife years in advance, buying hundreds of pottery figures and sculptures.

"The princes, princesses, wealthy ministers and distinguished nobles surrounded themselves with all the extravagances that money could buy, not only in life, but also in death," wrote the Chinese ceramics scholar Margaret Medley in a 1989 catalog for a show at the Dixon Gallery in Memphis, "Tang Sancai Pottery From the Collection of Alan and Simone Hartman."

Forty-eight pieces from the Hartman exhibition will be auctioned at Christie's in New York on March 20. The preview begins on Tuesday. "It's a good snapshot of life at the time," Mr. Tow said.

Mr. Hartman, who owns Rare Art Inc., a Manhattan gallery specializing in British and American silver and Chinese art, said that he and his wife, Simone, had collected Tang ceramics for 30 years and that he hoped to sell his pottery to one institution or collector for $1.3 million. If one buyer does not reach his reserve price, the collection will be sold in individual lots.

The Hartmans' pottery is all sancai (meaning three-colored) glazed earthenware in the colors of straw and amber (made from iron oxide) and green (from copper oxide). Sancai usually also includes blue glaze, which is rarer and was made from oxides with imported cobalt.

Other Tang sculptures are for sale in Sotheby's Chinese Ceramics and Works of Art auction on March 22. In addition, Mark Richards, a Los Angeles dealer, and Alberto Manuel Cheung, a private dealer in Manhattan, are bringing Tang ceramics to the Arts of Pacific Asia Show at the 69th Regiment Armory at Lexington Avenue and 26th Street, from March 22 to 25.

Mr. Cheung is selling a figure of a Tang woman playing a polo-like game on a horse whose legs are outstretched, similar to one exhibited last year at the International Museum of the Horse in Lexington, Ky. Nicholas Grindley, a London dealer, has two fine early unglazed Tang horses and two foreign grooms, which he is showing at the Kate Ganz Gallery, 25 East 73rd Street in Manhattan, from Wednesday through March 25.

The Hartman pottery is remarkable in its diversity. "The sculptures are of people who were part and parcel of Tang life," Mr. Tow said. There is a courtier, a groom, a falconer, an entertainer, a dancing lady, a foreign wine merchant and various animals. "They depicted native animals like buffalo and boar and foreign ones like camels and lions," Mr. Tow said. "The lion looks a bit like a pug, but they'd probably never seen a lion."

There are also jars, a water pot shaped like a beast, an ambrosia vase and a ewer with the head of a phoenix. The provenances of many pieces can be traced to the 1920's. Others were acquired at auction decades ago.

Tang artists were not the first to make tomb sculptures. Clay tomb figures go back to at least the third century B.C., before the Han dynasty. But Tang potters were more accomplished than their predecessors. The modeling is more subtle and individualized and the glazes are shinier and more colorful.

Perhaps the most extraordinary figure in the Christie's sale is a charming court lady seated on a rattan drum stool looking at a round mirror in her left hand. Her elaborate hairdo has two round buns. She rests her right foot on her knee, while one loose shoe, with a pointed toe, rests on the base. She wears a figure- revealing green gown with blue sleeves and has an amber throw on her shoulder.

Probably made in a mold, the figure has an unglazed head with a subtly carved, hand-painted face. The estimate is $170,000 to $200,000. "She cost me more than my apartment on Park Avenue," said Mr. Hartman, who bought his apartment in the 1970's.

Another striking piece is a blue water buffalo with striped brown horns, huge ears and a plaintive look in his eyes. His tender, a small boy, sleeps on his back, the tether in his hand. The boy's straw hat rests on his hip. "This is one of the earliest depictions of a boy on the back of a water buffalo," Mr. Tow said.

Mr. Hartman added, "I bought it 20 years ago at Christie's East when it was being sold as a fake." Its estimate is $80,000 to $100,000.

According to Christie's, the only known similar depiction is of a cow with a boy wearing a straw hat in the Freer Gallery of Art in Washington.