“The Packard people have really engaged the local community and authorities into feeling that this is their project,” said Daniel Berger, a Culture Ministry consultant who has acted as a liaison in the Packard project. “It’s made the monument become a source of pride, and income.”

Maria Paola Guidobaldi, the Culture Ministry official who is director of the site, went as far as to say that the support of the Packard Humanities Institute “allowed us to save the site.” The Italian government allocates some $4 million a year to Herculaneum, she said, but the Packard funds have permitted conservators to work in a more structured and forward-looking manner. “It’s been an extraordinary experience that we hope will continue because there is much more to be done,” she said.

A spate of crumbling walls and other mishaps at Pompeii, including an episode late this summer when a supporting beam collapsed at the so-called Villa of Mysteries, has put its preservation problems under a starkly unflattering spotlight. In 2011 the European Union allocated $135 million over four years toward the safeguarding of Pompeii, but experts concur that the problems there go beyond a lack of funds and include issues of management and bureaucratic inertia.

But officials at Herculaneum say that this site was not significantly better off when the Packard team arrived in 2001. (Herculaneum was described at a European conference in Rome in February 2002 as the worst case in the world of an archaeological site in extreme decay with no civil war to justify it.)

“It was a total disaster but with very complex reasons that took time to understand,” said Sarah Court, a spokeswoman for the Herculaneum Conservation Project, recalling that about two-thirds of the ancient city was closed to the public, and degradation — exploding mosaics, collapsing roofs, flaking frescoes — was widespread.

More integrated management practices and the opening up of the inflexible, top-down approach that is typical of Italian bureaucracy has helped to put Herculaneum on a more successful path. New forms of support have also been cultivated, and collaborations have been undertaken with other nongovernment partners, both Italian and international, in support of the public heritage authority.