The transfer is the culmination of an extensive investigation by U.S. Immigration and Customs Enforcement's Homeland Security Investigations to restore the true provenance of the vessel, a kalpis, officials said.
The kalpis, a ceramic vessel used in ancient times for holding water, shows a picture of pirates being transformed into dolphins by the god Dionysos. The vessel dates to about 510 B.C. and is valued at about $665,000.
Officials say the vessel was smuggled out of Italy after an illegal excavation before 1981. It was sold in 1982 to the Toledo Museum of Art by art dealers Gianfranco and Ursula Becchina, officials said. The Becchinas had bought it from convicted art smuggler Giacomo Medici.
Officials alleged the Becchinas misrepresented the true provenance of the vase to the museum by providing falsified documentation. The Toledo Blade reported Tuesday the Becchinas admitted forging documents to make the acquisition look legitimate.
Since 2007, more than 6,600 artifacts have been returned to 24 countries, including paintings from France, Germany, Poland and Austria, 15th to 18th century manuscripts from Italy and Peru, and cultural artifacts from China, Cambodia and Iraq, HSI said.