"The World of Khubilai Khan: Chinese Art in the Yuan Dynasty" at the Metropolitan Museum of Art is filled with treasures from museums around the world. Besides their beauty and rarity, they pose a question -- how monolithic is Chinese art?

At a time when China is espousing ethnic purity, this question has ramifications in the present day.

The exhibition begins with two stunning carved marble figures, each over ten feet tall, which were found in 1997. Both figures were probably part of an identical pair, placed leading the way to a tomb. One is Chinese in appearance, a "Civil Official," self-contained, with his robe falling into elegant pleats. The other, with bulbous features and gnarly-detailed battle dress with sword, a "Military Official," looks -- well, very different, yet they come from the same site dating to the Yuan (1271-1368).

The Mongol Genghis Khan’s grandson, Khubilai Khan, declared himself the head of the Yuan Dynasty in 1271. Under this scion of Mongol invaders, China was unified into a far-reaching empire for the first time since 907 CE. For more than 300 years, a series of nomadic invaders had swooped down from the northwest and captured and lived in what we now know as China.

China had become a smaller and smaller empire, plagued with internal problems while continuing to produce remarkable art. Militarily, it grew weaker as first the Khitan, who ruled as the Liao, and then the Jurchen, who ruled as the Jin, held sway over northern China. Other groups had carved out smaller areas. Finally, the Mongols arrived, spreading their hold over more and more territory.

Genghis Khan first incorporated every tribe on the Mongolian steppe under his control, learning and using their military expertise along with his own. Under his offspring, China’s shrunken Southern Song Dynasty finally succumbed to the Mongols.

Until recently, it was thought that Khubilai Khan, in settling down to rule his vast empire, had simply "gone Chinese," mirroring the Southern Song court to administer his holdings. But research and recent archeological finds, such as these marble statues, present an altered picture.

As much as the Mongols became Chinese, the Chinese became Mongols, and maybe that was not such a bad idea. The adaptations that occurred in the resulting blended culture are diligently traced in the more than 200 textiles, metalwork, ceramics, lacquer, scrolls, calligraphy, sculpture, architectural ornaments and other decorative works in "The World of Khubilai Khan."

So what was new? For one thing, an emphasis on gold objects and gold textiles. Nomads had always loved gold. They prized small gold objects and clothing over less portable painting and sculpture. In Khubilai Khan’s new capital of Dadu, now Beijing, only the Khan and members of the elite wore cloth of gold, a special weave of silk with gold thread, with the gold showing on the front of the fabric. A swatch is visible near the entrance of the show and a larger one in the final small gallery, a mini-survey of gold textiles that’s a marvelous show all by itself.

At first only collars and cuffs of cloth of gold were worn, but eventually whole garments were fashioned from it. A robe with some of the intricate patterns still visible, even if the gold has disappeared, hints at how dramatic such a garment would have been when worn at court. More than half the court workshops were devoted to textiles, especially cloth of gold, and included skilled weavers, which Khubilai Khan had transported from other parts of his domain.

Gold belt plaques, jewelry, and serving vessels, including a spectacular dish in the form of four "ruyi," or ritual scepters, are among other lavish items on display that the Mongols used.

The Mongols took over most of the ways of the Song court, yet being pantheists, they needed a state religion with rituals and clergy to enhance the legitimacy of their reign. One of Khubilai Khan’s wives was a Tibetan Buddhist, so Tantric Buddhism was favored at court, but in accord with the Mongol tradition of allowing conquered peoples to worship as they desired, all religions were allowed. China would never again be as tolerant about religion.

Under the Mongols, the arts reflected this relaxed atmosphere. A seated Buddha in gilt bronze looks Indo-Himalayan, but has very large feet that probably mean the artist was Chinese. A large pile carpet with a prunus, or plum branch, an old Chinese motif, has pseudo-Kufic script around the edges, suggesting an Islamic connection.  Other works are influenced by several branches of Buddhism, even Nestorian and Manichaean Christian pieces.

Painters made scrolls for both Daoists and Buddhists, often using the same imagery for both sets of clients. An especially lovely scroll in ink, color, and gold represents Beidou or the "Nine Stars of the Northern Dipper," which we would call the Big Dipper. Followers of either religion could have used it, as both venerated this constellation. Each of the nine stars is personified by a figure and holds a name plaque as they sashay through space.

The theater was the most popular of the arts during the Yuan. For the first time, all sorts of plays and skits were performed, with and without music. This would eventually result in the Beijing opera. A replica of a modal of a stage with five actors from the earlier Jin gives a good idea of what a Yuan theater would have looked like.

Another bit of stylish architecture is a "dragon’s snout" roof-ridge ornament. In glazed pottery that has retained its color, this more than six-feet-tall snarling beast illustrates the Yuan Dynasty development of these decorative creatures into dynamic, open-mouthed wonders. In general, a more realistic, three-dimensionality can be found during the Yuan.

Pottery figures of actors were popular, another manifestation of the increasing interest in three-dimensionality. And lacquer, with its deep carving, reached its zenith in this period.

Surface decoration also received fresh attention. Blue-and-white porcelain started during the Yuan with the arrival of cobalt blue from Iran as a result of increased trade. In turn, blue-and-white wares joined other ceramics as an export staple during the Yuan. Its popularity throughout the world led to increased exports, which the Mongols encouraged, although they don’t seem to have valued blue-and-white porcelain as much as foreigners. Excellent examples of blue-and-white ware include a jar showing a scene from a play in which a character drives a cart pulled by two frisky felines.

Porcelain with underglaze red also made its debut during the Yuan. Appearing first as a splash across the surface of a vessel, this copper-based red was soon tamed as another color to brush onto small, defined surface areas.

But the most important artistic development to begin during the Yuan resulted from the Mongols elimination of the state examination system as a way to achieve high office. Many of the intelligentsia could no longer earn civil or court offices. Some found other ways to get positions; others retreated into the countryside as Buddhist monks often did. Many turned to painting, setting the stage for the literati painters, the non-professional gentleman-scholars of the Ming, the next dynasty.

A key work in the development of the literati painters -- and a very beautiful one -- from the Yuan is Gong Kai’s poignant "Noble Horse," an ink painting with equally beautiful calligraphy by the artist.  In his calligraphy the artist muses about his thin-ribbed creature, "who today laments over the bones of this noble steed," thereby referring to his own position as a left-over remnant of the Song.

There are many pictures of horses from the Yuan. The Mongols loved horses and so did the Chinese. But only the Chinese also saw them as symbols of intellectuals of all sorts, who would soon find other ways of celebrating their withdrawals, forced or elective, from public life.

The Metropolitan has rounded up a number of other important scrolls by Yuan painters and calligraphers. Don’t miss Zhao Mengfu’s paintings or his vigorous "fist-sized" calligraphy. Not being content with this accomplishment, the evolution of literati painting is treated in even more depth in a related exhibition pulled from the museum’s own collection in the China galleries. It’s called "The Yuan Revolution: Art and Dynastic Change." But save that show for another day.

There’s plenty to see in "The World of Khubilai Khan" first.

"The World of Khubilai Khan: Chinese Art in the Yuan Dynasty," Sept. 28, 2010-Jan. 2, 2011, at the Metropolitan Museum of Art, 1000 Fifth Avenue, New York, N.Y. 10028.

N.F. Karlins is a New York art historian and critic.