With a half-dozen wooden art shipping crates laden with a smorgasbord of ancient artifacts as a backdrop, Italian and American officials on Wednesday celebrated the continuation of a 25-year collaboration that has returned thousands of illegally trafficked objects to Italy.

“The United States is, in every respect, Italy’s closest ally in the fight against the illicit trafficking of cultural property,” Italy’s culture minister, Alessandro Giuli, said at an event staged to recognize the return to Italy of trafficked objects and stolen artworks recovered from American museums, auction houses and private galleries over the past year.

The artifacts, which included Etruscan vases, Roman-era bronze and marble statues and busts, but also Byzantine coins and a 13th-century manuscript page, were identified after investigations by Italy’s art theft police in collaboration with different U.S. agencies, among them the Manhattan district attorney’s office, the F.B.I. and Homeland Security Investigations.

“Our two governments are well aware that theft, illegal excavations, and illicit exportation are crimes committed against the public good,” and both countries are “committed to combating this threat to the world’s cultural heritage in increasingly innovative, and effective ways,” Mr. Giuli added.

The photo-op camaraderie came at an especially low moment in U.S.-Italy relations. Earlier this month, after President Trump criticized Pope Leo XIV, Prime Minister Giorgia Meloni got a Trumpian tongue-lashing for having jumped to the pope’s defense.

Ms. Meloni said last week that she hadn’t spoken to Mr. Trump since their spat, but she expressed her support to the president after a gunman attempted to attack him over the weekend.

The at-times rocky relationship between art-rich Italy and art-hungry American museums and collectors was encumbered for decades by judicial investigations and court cases that often ended with a begrudging restitution of artifacts. Many cases remain open, like Italy’s claims on a bronze statue at the J. Paul Getty Museum in California.

In 2000, the two countries reached a cultural property agreement regarding importation restrictions that “has become a cornerstone of international efforts to combat the illicit trafficking of cultural property,” Italian officials said earlier this year at a commemorative event for the agreement.

Patty Gerstenblith, the director of the Center for Art, Museum and Cultural Heritage Law at DePaul University, said in an interview that the agreement has “been very effective in efforts by U.S. law enforcement in preventing undocumented antiquities from entering the U.S., returning these, and as a training tool for law enforcement.”

She added that it has also been useful in establishing a framework of cooperation between the two countries in cultural heritage, and encouraging loans to U.S. museums.

The agreement, renewed last December, covers import restrictions and only federal agencies can enforce it. In recent years, the Manhattan district attorney’s office in New York, though not a participant in the agreement, has taken center stage in multiple high-profile restitutions to Italy.

According to its own records, since its creation in 2017, its Antiquities Trafficking Unit has recovered more than 6,200 antiquities valued at more than $485 million, and has returned more than 5,860 to 36 countries.

The trove of nearly 340 artifacts returned on Wednesday showed the scope of the collaboration with American agencies.

Each object is the protagonist of its own nefarious back story.

The most prized piece, investigators said, was a marble head of Alexander the Great that was stolen from a Rome museum in 1960. It “was acquired in good faith” by Alan Safani of the Safani Gallery in 2017, according to a statement by the Manhattan district attorney’s office, but was seized by that office a year later. The gallery opposed the restitution and instituted a judicial process before a federal court of New York, which ruled in Italy’s favor last year.

“Protecting cultural heritage strengthens the rule of law and builds trust between governments and people,” Tilman J. Fertitta, the American ambassador to Rome, said at the ceremony. “When stolen art returns, both nations benefit. Italy regains its history, and the United States reaffirms its commitment to justice and cultural preservation.”

Also back is a first-century bronze winged satyr identified a year ago in an auction catalog, 50 years after the work had been stolen from archaeological deposits at the Herculaneum excavations.

For their part, Homeland Security Investigations assisted Italy in recovering 15 gold coins dating to the Byzantine era, part of a theft in 2009 in which 388 gold coins were stolen from the Archaeological Museum of Parma. They were tracked down in various specialized auctions.

The F.B.I. recovered from Los Angeles dozens of ancient artifacts in bronze, clay and marble that one investigator identified as having belonged to Jerome Eisenberg, an antiquities dealer who died in 2022. Investigations ascertained “their origin from clandestine excavations of Magna Graecia necropolises carried out in central-southern Italy, with the consequent illicit export to the United States,” the Italian authorities said in a statement.

More than 20 of the pieces focused on at the ceremony had been seized from the Metropolitan Museum in New York by the Manhattan district attorney’s office. Nine of the artifacts from the Met were part of a restitution announced in March that also included six rare books stolen from a Jesuit archive in Rome that had been appraised at $400,000.

The Met objects included two Greek ceramic drinking cups from about 500 B.C., a pair of Roman silver drinking cups from around the first century and a pair of gold earrings from the fifth century B.C.

In a statement this year, the Met said it had an “ongoing commitment to responsible collections stewardship.”

Jack Schlossberg, the grandson of John F. Kennedy, has built his campaign for a New York City House seat around turning the page on the Democrats’ old guard.

Yet when he debuts his first paid advertisement on Wednesday, the 33-year-old candidate has chosen his party’s oldest living leader, Representative Nancy Pelosi of California, to do the talking.

The choice reflects the unique challenge Mr. Schlossberg faces ahead of a marquee June primary against more seasoned rivals. He may have star power and youth, but he is still trying to persuade aging voters who form the Democratic base that he is serious and experienced enough to represent a storied Manhattan district — home to corporate chieftains, media empires and cultural meccas.

The 30-second ad, which was shared first with The New York Times, uses Ms. Pelosi, a former House speaker, to make his case. In it, the congresswoman, 86, speaks directly to the camera to say that Mr. Schlossberg has “a deep sense of duty” and the kind of energy that could help propel Democrats back to power nationally.

“This moment calls for leaders who understand the stakes and how to deliver for the people they serve,” she says, sometimes over clips of him campaigning. “Jack Schlossberg is that kind of leader.”

Mr. Schlossberg is among the first candidates in New York’s 12th District to start spending on paid media. But a handful of super PACs funded by competing A.I. companies and former Mayor Michael R. Bloomberg have already burned through millions of dollars trying to sway voters toward or away from his rivals.

Mr. Schlossberg’s outlay will be relatively modest in comparison. The campaign said it would initially spend $70,000 on digital platforms, and eventually add more digital spending and $250,000 in broadcast TV time — a relatively small sum in the nation’s most expensive media market.

Mr. Schlossberg, who has reported inherited assets between $10 million and $32 million, said he would not be spending any of his own money in the race. He does not have a super PAC behind him.

While there has been no real public polling to date, private polls released by several of Mr. Schlossberg’s rivals have all narrowly put him in the lead.

With two months left until Primary Day, two state assemblymen — Alex Bores and Micah Lasher — are not far behind; followed by George Conway, a former Republican turned high-profile antagonist of President Trump, and Nina Schwalbe, a public health expert. Because the seat is safely Democratic, the primary winner will almost certainly win the general election to replace Representative Jerrold Nadler, who is retiring.

Mr. Schlossberg, earlier known for a head-turning social media presence, has largely tried to portray his opponents as old-fashioned, risk-averse establishment figures who have not been able to check Mr. Trump. They, in turn, have raised doubts about the thinness of his résumé, which includes no long-term traditional work experience, elected or otherwise.

In an interview, Mr. Schlossberg said it was an obvious choice to turn to Ms. Pelosi, who is perhaps her party’s most respected elder stateswoman.

“Speaker Pelosi is the backbone of our party,” he said. “She most importantly understands better than anyone how the House of Representatives works and what the Democratic Party needs right now.”

Yet embracing Ms. Pelosi may also have its costs, complicating Mr. Schlossberg’s attempts to position himself as an outsider and a fresh face by reminding voters of his family’s deep ties to the Democratic establishment.

Mr. Schlossberg said he believes he first met Ms. Pelosi when he was in high school. Alongside his family, he presented her with the John F. Kennedy Profile in Courage Award in 2019.

The candidate said Ms. Pelosi asked to meet with him in her Washington office before she endorsed his campaign in February.

“I printed out all my plans I have for the district and the country,” he said. “She read them over and quizzed me.”

An earlier version of the ad shared with The Times included footage of Mr. Schlossberg and Ms. Pelosi spending time with his mother, the former ambassador Caroline Kennedy, and his niece, the daughter of his sister Tatiana Schlossberg. (Ms. Schlossberg, who was an environmental journalist, died in December after a fight with blood cancer that she chronicled in a widely read essay.) That footage was cut from the final ad before it was distributed.

In the interview, Mr. Schlossberg said he exempted Ms. Pelosi from his critique of this party’s aging officials — and argued voters would, too.

“I put her in a category of her own,” he said. “She has magic that doesn’t age. It wins.”

The provocative painting seemed like an authentic work by Andy Warhol, depicting a nude man and woman gazing at each other with colorful shading around their bodies.

But the piece was a well-disguised counterfeit, among more than 200 fakes of works by artists like Banksy, Picasso and the Native American painter Fritz Scholder, which sold for a total of more than $2 million. Many of the works were made by an artist in Poland, and commissioned by a father and daughter living in New Jersey.

On Tuesday, the father and daughter, Erwin Bankowski and Karolina Bankowska, pleaded guilty in Federal District Court in Brooklyn to running a scheme to sell the counterfeit works.

The duo “painted themselves as purveyors of fine art while selling lies on canvas to unsuspecting collectors,” Joseph Nocella Jr., the U.S. attorney in Brooklyn, said in a statement.

Federal guidelines call for a prison sentence of 33 to 41 months for each defendant. Both Mr. Bankowski and Mr. Bankowska are citizens of Poland and face deportation after serving their sentences. They are set to be sentenced on Aug. 5.

Todd Spodek, a lawyer for Ms. Bankowska, 26, said his client had accepted responsibility for her crimes. Jeffrey Chabrowe, a lawyer for Mr. Bankowski, 50, said his client also accepted responsibility and had “made a terrible decision to support his family.”

Counterfeit art schemes date back thousands of years. Many forgers in recent decades have pulled off their operations by faking a work’s provenance, or documented ownership history, which elite art collectors check to determine authenticity.

Famous art forgers include Wolfgang Beltracchi, a German man who says he painted in the style of more than 100 artists, and Mark Landis, who has donated numerous fakes to dozens of museums. Two art forgery rings in Thunder Bay, Ontario, manufactured thousands of fake paintings presented as works by Norval Morrisseau, one of Canada’s most celebrated Indigenous artists.

Mr. Bankowski and Ms. Bankowska went to great lengths to conceal their efforts. In addition to creating the fake provenances, sometimes by using forged stamps from art galleries, they told buyers that the pieces were from art galleries that had since closed, prosecutors said. That made it harder for buyers to verify that the pieces were real.

The pair’s collection included splotchy pieces, often with strong political overtones, that were sold to reputable galleries and auction houses around the United States. One fake of a work by Banksy, the anonymous British street artist, that protested the Iraq War sold for $2,000. A knockoff of a painting by Raimonds Staprans, a Latvian American visual artist who died in January, sold for $60,000.

Mr. Bankowski and Ms. Bankowska also sold works that they claimed were made by Native American artists, earning a rarely used federal charge: the misrepresentation of Indian goods and services. One of the counterfeits was a fake of a landscape by Richard Mayhew, a painter of Black and Native American heritage; it sold for $160,000, prosecutors said.

Mr. Spodek, who has represented many people accused of elaborate scams, said his clients had taken great care to ensure the knockoffs looked authentic. He said the replicas that the father and daughter commissioned were “identical” to the originals.

“It’s not just selling on eBay,” Mr. Spodek said.