ROME, Jan. 18 -- When the infamous emperor Nero fell from power in A.D. 68, weakened by military revolts, his successors decided no personal trace of his reign should remain. They covered with debris the giant and sumptuous Domus Aurea -- the Golden House -- that he built on a hill in central Rome. They replaced an adjacent artificial lake with the Colosseum.
The entombment of the palace was meant to make everyone forget Nero. Instead, it conserved, as if in amber, his residential compound as few ancient sites in Rome have been preserved. This week, almost 2,000 years after Nero's rule, Rome city officials unveiled a new find from the palace that offers a tantalizing hint of the treasures buried beneath the hill. It is a large mosaic, more than 9 by 6 feet, showing naked men harvesting grapes and making wine, a typical illustration for a Roman palace of the time. Three of the men are stomping on grapes in a vat. One plays a double flute. They all seem to be having fun.
An ancient fresco, before and after restoration, depicts an imperial city, perhaps Rome. The fresco was discovered in Nero's Golden House, a structure that was covered with debris by the emperor's successors after he died so that no trace of his reign would remain.
(Courtesy Of Rome City Government)
The mosaic adorns a giant arch buried in Colle Oppio, the hill on which Nero's palace stood. The arch was probably part of a large hall. Grottoes and tunnels extend from four exits -- leading to as yet unknown finds.
"Colle Oppio is a giant scrap yard," said Eugenio La Rocca, the city's adviser for monumental assets. "There is doubtless much more underneath. Everything has been sealed. There are acres of a city quarter in there."
The mosaics were found more than 40 feet below the ruins of the Trajan Baths, a large structure built over the Golden House more than half a century after Nero's death by suicide.
Parts of the palace were first uncovered in the late 15th century after lying hidden since imperial days. Renaissance artists flocked to the site's caves and tunnels to copy the mosaics and frescoes. Scavengers made off with sculptures.
In recent years, items from other sections of the palace have come to light. In 1998, workers who were cleaning out and shoring up a cave discovered a fresco that showed a view of an imperial city, possibly Rome. They soon discovered a mosaic of a philosopher and his muse.
Experts are split over whether these artworks were part of Nero's estate or dated from an earlier building that he knocked down to make way for his mansion. He constructed the Golden House after Rome burned in A.D. 64. Rivals blamed the conflagration on Nero.
Today, only a small part of the palace, all underground, is open to the public. It will be a while before the arcades and room found beneath the Trajan Baths are open for public viewing, city officials said, because of the slow pace of exploration and reinforcement of the passages. Excavations are entirely in the hands of the municipal government, proprietor of the Colle Oppio, the site of a public park. The Italian government provides no funds.
Private money appears out of reach, given the uncertainty of what might be found. "It's one thing for companies to pay to restore a work of art that exists. You know what you are getting at the end of it," said Gianni Borgna, city hall's cultural adviser. He estimated that it would take 500 million euros -- about $650 million -- to excavate all of Colle Oppio.
The mosaic's discovery continues a trend in Italy of excavating ancient sites deeper underground rather than expanding existing archaeological zones along the surface. In Pompeii last spring, a pre-Roman temple was discovered beneath a later temple at the front entrance to the city. The decision in Pompeii to dig downward stemmed in part from lack of funds to clear and open above-ground spaces.
At other sites, the reason to dig down is simply to go back further into history. Atop Palatine Hill, which overlooks the imperial Roman Forum, pre-imperial buildings, complete with slave quarters in their basements, were recently found beneath newer structures.
South of the Colosseum, a house reputed to have belonged to a pair of Roman generals who converted to Christianity was discovered beneath the Sts. John and Paul Church. The house, now restored, features a painting of a Christ-like figure, arms extended.
This kind of exploration means the future of tourism may be underground, Borgna said, especially in a city built upon layers of history. "Eventually, when these caves and grottoes are open to the public," he said, "it will be like visiting the catacombs. It will be a subterranean experience."