The Republic of Peru has quietly filed a lawsuit against Yale, officially turning a nearly century-long dispute over the rightful ownership of Inca artifacts into a legal battle.

By late Tuesday, Yale had still not been formally served with the 31-page complaint that was filed Friday in the United States District Court for the District of Columbia. But the lawsuit — in which Peru asks for the immediate return to Machu Picchu of all the artifacts excavated by Yale explorer Hiram Bingham III — comes as a grave setback to University officials who had hoped to resolve the conflict amicably and now say the lawsuit has no basis.

[ydn-legacy-photo-inline id=”11491″ ]

“It’s very disappointing,” University President Richard Levin said in a telephone interview Tuesday night. “We worked very hard to try to steer a responsible course on this matter and we have been on numerous occasions within a hair’s distance of settlement with the Peruvians.”

Indeed, as late as September of last year it had seemed certain that Yale and Peru would reach an agreement over the fate of the artifacts. The memorandum of understanding signed between the parties then would have returned most of the objects to Peru within a few years, though some objects would have remained at Yale for up to 99 years.

Now, according to the complaint, Peru is seeking “the immediate return of all such property as well as damages that it has suffered on account of Yale’s persistent breach of its obligations and profit at the expense of the people of Peru.”

The lawsuit cites Peruvian law dating back to the 19th century as the basis for the nation’s claim to the objects that were excavated between 1911 and 1915 and are now housed at the Peabody Museum of Natural History. But Peru is not just seeking the repatriation of what the lawsuit calls “mummies, skulls, bones and other human remains, pottery and utensils, ceramics, objects of art and other items.”

Instead, Peru is also suing for compensation — the amount of which would be determined at trial — in connection with alleged breaches of agreement on Yale’s part. There are 14 causes of action in Peru’s complaint, including one that accuses Yale of acting fraudulently by not conducting sufficient scientific research on the objects.

In e-mails to the News, University General Counsel Dorothy Robinson declined to discuss the specifics of the lawsuit, saying that Yale had not yet reviewed the complaint in full.

“Clearly it is a case where there is good reason for both sides to reach a creative, constructive resolution,” Robinson said Tuesday. “We will, of course, defend the suit.”

Yale spokesman Tom Conroy also issued a statement Tuesday, in which he decried the Peruvian lawsuit.

“The claims asserted by Peru are barred by the statute of limitations,” Conroy said, “and would have been without merit even if they had been filed within the legal time period.”

William Cook, a partner with the Washington law firm DLA Piper who represents Peru, declined comment Tuesday.

Peru’s ambassador to the United States, Felipe Ortiz de Zevallos, said in an e-mail exchange with the News on Tuesday that the lawsuit is an “extremely sensible and complex” matter.

While de Zevallos declined to comment further, the matter is indeed complex, and has been for some time. September’s memorandum was never finalized as Peruvian politicians split over the question of how many artifacts should be returned immediately. Yale officials said they found it difficult to negotiate with Peru because of the country’s political landscape.

“The Peruvians have consistently backed off from their decisions and reneged on their positions,” Levin said Tuesday.

Ironically, the lawsuit itself comes as little surprise to Yale. Peruvian officials had hinted since April that they would sue Yale, and those intentions were bolstered by the country’s Council of Ministers in November, when it approved in principle the filing of a lawsuit. Peru’s previous administration, which left office in 2006, had also threatened legal action against Yale.