For more than 1,500 years, from the end of the Bronze Age until the arrival of Islam in the 7th century, a civilization of traders flourished on the tip of the Arabian peninsula. Unlike Arabs to the north, they were not itinerant. They stayed put, grew rich off trade in frankincense and myrrh, and raised stone cities, temples and dams to capture the annual monsoon rains, with which they made the desert fertile.

To mark great events and the basic passages of life -- dedications of new buildings, deaths of their notables -- they wrote in a script as vertical and angular as Arabic is linear and sinuous. With changes in the global economy, regional sectarian strife, and finally the spread of Islam, their world faded. The carved, cast and written remains of their culture are now on display at the Arthur M. Sackler Gallery in an exhibition called "Caravan Kingdoms: Yemen and the Ancient Incense Trade."

Our engagement with the ancient past is governed by archaeological glamour. The Egyptians, the Greeks, the Romans, the Mayans -- they make persistent claims upon our imagination. Other civilizations, ones that left, say, artifacts but not architecture, or tombs but not literature, are like so many orphans pleading for but never receiving consistent attention. The people who lived in what is now Yemen are in this latter category. The written culture they have passed down to us never rises to the level of literature, and while their wealth left a strong impression on the ancient world, their reach was never as far or as lasting as that of the Egyptians, Romans or Greeks.

The most recognizable thread connecting us to ancient South Arabia is a thin, biblical one: Among the most powerful and respected of their small kingdoms was Saba, known to readers of the Bible as Sheba. For what may have been propaganda purposes, the author of the Old Testament book of Kings tells us that the Queen of Sheba visited Solomon, tried to stump him with questions, failed and left altogether wowed by the magnificence of his court. "When the Queen of Sheba saw all the wisdom of Solomon and the palace he had built," says the Bible, "she was overwhelmed." Scholars are dubious about the existence of a female ruler from Saba and consider her visit very unlikely ("almost preposterous," writes Nigel Groom in the exhibition catalogue). But it demonstrates Saba's reputation in the ancient world -- and uses that reputation to glorify the Jewish king.

The people who inhabited Saba, and the kingdoms around it -- often at war, though occasionally united and formidable -- remain elusive, despite the best efforts of the curators of this new exhibition. The subjects' carvings, in alabaster, are stylized and strangely humble. Among the best preserved statues on display are boxy, human figures, a few feet high, with their forearms held out at right angles to the body. Some statues have slight, serene smiles on their faces. Smiles, across the span of centuries, are enigmatic. The distant past, which so often comes down to us through the memory of warriors, priests and royalty is almost always serious. Not these figures. They seem more relaxed, more comfortable with their silence, than the statues of other cultures.

Among the most fascinating objects are funerary carvings, with detailed alabaster heads set into much rougher and more primitive limestone pillars. It's as if the limestone is a shroud over the softer, more lifelike facial carving.

"I don't know anything like it from other ancient Near Eastern cultures," says Ann Gunter, curator of ancient Near Eastern art at the museum. Gunter says that the emphasis and care lavished on the human face in these oddly composite sculptures are distinguishing features of the ancient South Arabian civilization.

The ancient South Arabians also carved altarpieces that mimicked the architecture of their temples. These have a surprising affinity with architectural styles we might recognize from Vienna in the early 20th century, a rectilinear cleanliness and symmetry reminiscent of the Secession or Art Deco.

Gunter sees an aesthetic unity in the various products of the region, and "a formal abstraction that is extremely appealing to modern taste." As she readily acknowledges, it's hard to say that any culture so removed from ours would consider its representations abstract. And the reason abstraction appeals to us is that we sense in it qualities of innovation, distillation and intellect that are entirely our projection on artists who worked within the bounds of tradition and instinct.

But the word is inescapable. As you progress through the exhibition, the growing Hellenistic and Roman influences become more apparent, as boxy, stylized figures yield to lifelike faces and bodies. One of the exhibition highlights, a rearing horse borrowed from Dumbarton Oaks while that museum is under renovation, is thrillingly realistic. The "abstraction" of the earlier, more purely indigenous rooms feels centuries away.

In speeches given before the opening of the exhibition, both the Sackler's director, Julian Raby, and the Yemeni minister of culture and tourism, Khaled Abdulla al-Rowaishan, emphasized the continuity in Yemeni culture. But this continuity in ancient Yemeni culture shouldn't be confused with a strong connection to the present. In fact, the world of ancient Yemen is very discontinuous with the Muslim world that supplanted it. Its script is gone, its temples in ruins, its gods forgotten. Its representations of the human figure would be taboo throughout much of the Islamic world. And because early Islamic culture was particularly hostile to the "heathen" past, it seems as if societies such as Saba faded with alacrity -- though future discoveries and more scholarship may shed light on the apparently rapid decline.

Still, al-Rowaishan said, "Yemen is the mother of Arab civilization." Perhaps. Gunter says that some aspects of the ancients -- their literacy, their building techniques -- are continuous with modern Arabic civilization. But the one enduring fact of history is its value -- like the Queen of Sheba -- as propaganda for the present. Nothing domesticates a culture like the quiet sanctification of appearing in a prestigious museum. And beneath the argument that modern-day Yemen -- an ally in the war on terror, but also a fertile ground for anti-Americanism -- is continuous with the people who made these lovely artifacts is a deeper desire to connect a country that many Americans find frightening with a past that can be enjoyed purely as visual spectacle. Those are the politics. Fortunately, they don't detract from the pleasure of "Caravan Kingdoms."

The Sackler Gallery exhibition includes this limestone temple altar circa 8th century B.C. Later artifacts, such as this bronze rearing horse, circa A.D. 200, are marvelously realistic.From left, a bronze sculpture of Madikarib, from the 6th or 7th century B.C.; an alabaster statue of Maadil Salhan, king of Awsan, from the 1st century B.C.; and a female head from the 1st century A.D. All are in the "Caravan Kingdoms" exhibition, at the Sackler Gallery through Sept. 11.