Sir Barry Cunliffe, an Oxford archaeologist and head of the excavation, told The Times of London that the 19th century diggers may have been confused by the presence of another, later villa on the site. The earlier building did become an outbuilding later in its life. He described the earlier villa as being the size of an Olympic swimming pool with residential quarters for the owner at one end and a public area for meetings and legal hearings at the other.

"It would have sung out the status of the owner," Cunliffe said. "It's a very impressive building, absolutely magnificent. It could have been seen for miles around."

The residential area had all the luxury touches of Roman life 18 centuries ago, including underfloor heating.

The new discovery was lying about 3 feet below ground with much of its structure still in place. But the next step may be to cover it over again to preserve it until the day when the money for a complete excavation is available.

The site is owned by a charitable trust. Kevin Hicks, one of the trustees, said that 250,000 pounds -- around $500,000 -- would be required for the excavation.