The objects had been found in five Swiss warehouses belonging to a Sicilian antiquities dealer, and were brought back to Italy after a long-running investigation.

The Italian authorities on Wednesday displayed for the first time a trove of more than 5,000 archaeological artifacts that had been looted from the country and were discovered more than a decade ago in Switzerland, before they could sold on the illegal antiquities market.

The objects -- black-figure and red-figure pottery, wall frescoes, marble plaques, jewelry, bronze statuettes and urns -- had been found in five Swiss warehouses belonging to a Sicilian antiquities dealer, and were returned to Italy after a long-running investigation.

"It is by far the most significant recovery in history in terms of quantity and quality," with an estimated value of more than 50 million euros, or $58 million, said Gen. Mariano I. Mossa, the chief of the cultural heritage division of the Carabinieri, Italy's national police.

The artifacts were looted by tombaroli, as the robbers of ancient graves are known, from sites throughout central and southern Italy, and date from a period stretching more than 1,000 years, from around the 8th century B.C. to the 3rd century A.D. Many are museum- quality pieces.

"There's a little of everything, because the people who collect artifacts in this terrifying manner are open to anything, from anywhere, and especially the south, which pays a hefty price for being archeologically rich," said Mariarosaria Barbera, the Ministry of Culture official who oversees Rome's ancient artifacts.

Seeing the objects together -- for the news conference on Wednesday they were arranged on the floor of four large rooms in the National Roman Museum -- should give cause for reflection on "the immense massacre" of Italy's archaeological heritage, Ms. …