Augustus had an image problem.

The first Roman emperor wanted to carve his political propaganda in stone, portraying himself as the stern military hero who ended civil strife by defeating the decadently un-Roman Antony, Cleopatra's lover.

But he also wanted to make himself a herald of peace, the man who gave Romans a new golden age, a new reason for joie de vivre in the epoch when B.C. became A.D. How to fix the contradiction?

It was no problem roughly 2,006 years ago for the senator or aristocrat who commissioned the rare marble altar recently purchased by the Michael C. Carlos Museum at Emory University: He simply threw together symbols of Apollo, the sun-god of order, with references to antiquity's naughty deity, Dionysus, god of wine and all other sensual pleasures.

"Antony had adopted Dionysus' imagery, Augustus replied by associating with Apollo, and together it's a kind of contradiction," said Francesco de Angelis, professor of Roman art at Columbia University. "But in the villas, they forgot contradictions. The senators who most likely commissioned this didn't give up the ideals Dionysus incarnated, the ideals of a pleasant life."

While about 30 altars from this era exist, the 46-inch tall altar now on its way to Atlanta from London is the only one known to have the mixed images, de Angelis said.

"This is a very deluxe object; it gathers together all the history of the Mediterranean," said Bonna Wescoat, professor of Greek art at Emory University. "This is Augustan art at its best."

London dealer Rupert Wace approached Jasper Gaunt, the Carlos' curator of Greek and Roman art, for the sale, Gaunt said. Wace got it from a French family who purchased it when one of Great Britain's best classics collections - that of the Marquess of Lansdowne - was auctioned off in the 1930s.

Gaunt jumped at the chance to get something rarely on the market and Thalia Carlos, wife of the late Michael C. Carlos for whom the museum was named, donated an undisclosed six-figure sum to buy it, Gaunt said. The purchase confirms the Carlos' place as one of the best collections of Graeco-Roman art in the country, said Michael Padgett, curator of ancient art at Princeton University Art Museum.

The altar's sheer sophistication speaks to the emperor's goal of making Rome the official heir of classical culture, Wescoat said. Augustus liked to brag that he had found a city of brick and made it into a city of marble. His age saw the beginning of widespread use of Carrara marble, the same Michelangelo used 15 centuries later.

But perhaps the most striking feature of the cylindrical altar today is what it shows of everyday life for the elite. The altar would have been used in a villa garden or private sanctuary for sacrifices of small animals or incense. Its images reflect the lush surroundings.

Four scenes - two alluding to Apollo and two to Dionysus - wrap around the altar. In one of the latter, a panther is about to lap up a bowl of wine - implying that the deity had tools to tame the wildest beasts. From a garland of grape leaves above, hangs a small disc with a cherub relief that looks uncannily like a Christmas tree ornament. It was an oscillum, made to swing in the wind blowing through the vineyards and trees to invoke fertility.

Once it clears customs, the altar will stand out as a truly imperial object among the Carlos' small but choice collection of ancient art, which includes such everyday works as a 14th century B.C. Minoan bathtub from Crete.