ROME The Torlonia family's collection of ancient marble sculptures has long been the stuff of legend for art historians and archaeologists. Hidden away in three large rooms in one of the aristocratic family's many Roman properties, the collection of over 600 marble, bronze and alabaster statues and reliefs has not been seen by outsiders for decades. Over the years, efforts by the Italian government to reach an agreement with the family to display or sell the works have been unsuccessful. Until now. On Tuesday representatives of the Culture Ministry signed an accord here with the Torlonia Foundation, a nonprofit organization that administers the family's assets, to display the works in public, starting with a show of at least 60 Greek and Roman statues in Rome. The public display of the works "has always been in the intent of the family," said Alessandro Poma Murialdo, the administrator of the Torlonia Foundation and the chief executive of Banca del Fucino, the Torlonia family bank. "The collection is the patrimony of humanity, as well as of the family." The exhibition in Rome will most likely be held in the Palazzo Caffarelli, which is part of the Capitoline museum complex, officials said on Tuesday, and it will then travel elsewhere in Europe and to the United States. Eventually, a permanent home will be found for the collection. The family accumulated the works in the 19th century, largely by buying existing collections, including statues belonging to Bartolomeo Cavaceppi, an 18th-century sculptor, antiquarian and restorer. Other works had been amassed by the Albani and Giustiniani families, which, like the Torlonia, are powerful dynasties with a taste for ancient art. Some pieces were excavated from the family's properties in and around Rome. Many of the statues had been repaired over the centuries, creating what Carlo Gasparri, an archaeologist who has been studying the collection since 1976 and is also involved in the exhibition, described as "a kind of laboratory, where ancient marble works have been continually reread through restoration, so we see the development of tastes of the last three centuries." In the 1870s the family opened a museum to showcase the collection in the Trastevere neighborhood, just off the Tiber River. It was closed in the 1960s, though many works had already been moved into storage. The only catalogs of the collection date to the 1870s and 1880s, among the first printed in Italy to use photographs. Salvatore Settis, the art historian and curator chosen by the family to curate the exhibition, described the catalogs as a "monumental work." The government has pledged to find what Dario Franceschini, the culture minister, described as a "prestigious location" for the collection in Rome, where most of the works can be shown. "I've never used the word historic in the last two years, but here we are at a historic moment," Mr. Franceschini said at the signing of the accord on Tuesday. The agreement was reached because "there was a new approach on the part of the ministry to a potential partnership between the public and private," Mr. Poma Murialdo said. "It could become a model for other similar cases." He added that Mr. Franceschini had been pressing for new measures and incentives to improve the relationship between the two sectors, though these were still at an "embryonic state." A central aspect of the accord is that the collection "travel around the world," Mr. Poma Murialdo said. "It is part of the agreement, the ministry wanted it, and we wanted it as well."