The room, part of Nero's Golden Palace, a sprawling residence built in the first century A.D., is thought to have been built to entertain government officials and VIPs, said lead archaeologist Francoise Villedieu.

The emperor, known for his lavish and depraved lifestyle, ruled from 37 A.D. to 68 A.D.

The dig so far has turned up the foundations of the room, the rotating mechanism underneath and part of an attached space believed to be the kitchens, she said.

"This cannot be compared to anything that we know of in ancient Roman architecture," Villedieu told reporters during a tour of the cordoned-off dig.

She said the location of the discovery atop the Palatine Hill, the rotating structure and references to it in ancient biographies of Nero make the attribution to the emperor most likely.

The partially excavated site is part of the sumptuous residence, also known by its Latin name Domus Aurea, which rose over the ruins of a fire that destroyed much of Rome in A.D. 64.

The purported main dining room, with a diameter of over 50 feet (16 meters), rested upon a 13-foot (4-meter) wide pillar and four spherical mechanisms that, likely powered by a constant flow of water, rotated the structure.

The discovery was made during routine maintenance of the fragile Palatine area, officials said.

Latin biographer and historian Suetonius, who chronicled his times and wrote the biographies of 12 Roman rulers, refers to a main dining room that revolved "day and night, in time with the sky."

Angelo Bottini, the state's top official for archaeology in Rome, said the ceiling of the rotating room might have been the one mentioned by Suetonius, who wrote of ivory panels sliding back and forth to shower flowers and perfumes on the guests below.

"The heart of every activity in ancient Rome was the banquet, together with some form of entertainment," Bottini said at the dig. "Nero was like the sun, and people were revolving around the emperor."

That part of the palace - which sprawled across nearly 200 acres (80 hectares) occupying parts of four out of Rome's seven ancient hills - offered a panoramic view over the Roman Forum and a lake, later drained by Nero's successors to build the Colosseum, Bottini said.

Described by Suetonius as one of Rome's most cruel, depraved and megalomaniac rulers, Nero often indulged in orgies and, fancying himself an artist, entertained guests with his own performances of poetry and songs.

However, Nero did not enjoy the frescoed halls and gold-encrusted ceilings of his Golden Palace for too long. It was completed in A.D. 68 - the year the unpopular emperor committed suicide amid a revolt.

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