The 24 pieces of gold jewelry, dated to 2400 B.C., were purchased by the Penn museum from a dealer in 1966, but were not accompanied by any documents that established their origin. The gold was sent to Turkey by courier over the weekend and almost immediately was put on display.
The move drew criticism from Ernst Pernicka, the scientist whose research led to the transfer. The analysis did not conclusively demonstrate that the jewelry was from Turkey, only that it was "consistent with" a Turkish origin, said Pernicka, a professor at the University of Tübingen in Germany. He predicted it would open the door for more such claims.
"The whole thing will only create problems for other American museums," Pernicka said.
But Julian Siggers, who became director of the Penn museum in July, said the agreement takes the inconclusive nature of the science into account.
"It's highly likely but it's not conclusive," Siggers said. "That's why it goes as an indefinite loan as opposed to being given back. . . . They're delighted to have this back, but I think everybody wins here."
Ertugrul Günay, the Turkish minister of culture and tourism, expressed gratitude to the museum. He said in a news release that the items were now in the "land to which they belong."
The agreement was prompted in large part by a speck of dirt.
When Pernicka and colleague Hermann Born came to Philadelphia to examine the jewelry in February 2009, they found that a tiny loop on one pendant was encrusted with earth.
Pernicka removed the dirt and took it back to Germany, where, using a technique called neutron activation, he found it contained a high level of arsenic. That amount of arsenic, 40 parts per million, is similar to levels found in northwestern Turkey, he said. But Pernicka, who also studied the metal itself, said he could not prove it was from Turkey, adding that Greece was a possible alternative.
This knowledge gap illustrates what can happen when artifacts are not excavated in an academic fashion, said C. Brian Rose, curator of the Penn museum's Mediterranean section and a professor of archaeology.
"There's no question that it was looted," Rose said. "We're just not sure of the exact place from which it was looted."
The Penn museum purchased the objects because of their similarity to others known to be from Troy - the city that inspired the Iliad, Homer's account of the Trojan War.
But officials were troubled by the uncertain origin of the objects, and the museum decided in 1970 it would no longer acquire undocumented artifacts. It was the first museum to make that move.
In a 2009 interview, a controversial antiquities dealer named Robert E. Hecht Jr. said he was the source of Penn's 24 pieces of gold.
Hecht said he bought the items from a middleman and did not know if they had been illegally excavated. He said he was not bothered by the lack of documentation.
"The main thing is the beauty of the thing," Hecht said.
That kind of sentiment is anathema to Rose and other archaeologists, for whom information about an object's origin is an invaluable source of cultural and historical knowledge.
Hecht was widely suspected of trafficking in illegal antiquities, most recently facing charges in Rome.
But in January, a judicial panel declared that the statute of limitations on the charges had expired.
The antiquities dealer, a Haverford College graduate and part of the family that established department stores in Baltimore and Washington, died several weeks later at 92.
Contact Tom Avril at 215-854-2430 or firstname.lastname@example.org .