Archaeologists repairing a Roman catacomb have discovered an unusual network of underground burial chambers containing the elegantly dressed corpses of more than 1,000 people, a Rome official said.

The rooms appear to date back to the second century and are thought to be a place of early Christian burial. Because of the large number of bodies deposited over a relatively short period, experts believe a natural disaster or epidemic may have occurred at the time.

The corpses, dressed in fine clothes embroidered with gold thread, were carefully wrapped in sheets and covered in lime. Balsamic fragrances were also applied, according to Raffaella Giuliani, chief inspector of the Roman catacombs, who spoke with Vatican Radio May 1.

The discovery will be officially presented in June by the Pontifical Roman Academy of Archaeology, which excavated the site in collaboration with Rome's Ecole Francaise and the University of Bordeaux in France.

Giuliani said the burial chambers were found accidentally in 2003, when experts were repairing a cave-in located in the Catacomb of Sts. Peter and Marcellinus, one of Rome's lesser-known catacombs that is closed to the public.

The archaeologists discovered a large room behind one of the painted walls of the catacombs, then a series of similar rooms.

"These were not galleries or cubicles, but big rooms completely full of skeletons. We had to work very carefully to excavate them without destroying them," Giuliani said.

"We were amazed at the high number of individual corpses found in these rooms," she said. The rooms appear to predate the catacombs, which were built in the third century.

Giuliani said the experts believe they were Christian burial places, in part because Christians of that time dedicated great care to burial. Early Christians buried rich and poor with great dignity, in expectation of the resurrection of the dead -- a fact that helps explain the presence in Rome of more than 50 miles of underground catacombs.