A terracotta head depicting the Greek god Hades that the J. Paul Getty Museum acquired in 1985 is being voluntarily sent back to Sicily, the museum has announced.

Getty officials said that the museum has worked with officials from Sicily during the last two years to determine whether it would be appropriate to return the artifact.

The museum said Thursday that the head's original location was the site of a sanctuary to the goddess Demeter in Sicily that was "clandestinely excavated" in the 1970s. The museum said the provenance was determined from the head's resemblance to four terracotta fragments found near Morgantina, Sicily, a famous archaeological site on the island.

The Getty bought the terracotta head of Hades in 1985 from New York collector Maurice Tempelsman, who had purchased it from London dealer Robin Symes. Getty records show the musuem paid $530,000 for it.

While researching their collection, Getty officials said they discovered the similarity to the fragments found in Morgantina. The Getty’s current curator of antiquities, Claire Lyons, is an archaeologist who dug at Morgantina.

In joint research with local archaeological authorities, the Getty determined the Hades mask was looted from the site’s sanctuary of Demeter and Persephone in the early 1970s.

Morgantina is the same heavily looted archaeological site in central Sicily where the Getty’s former statue of Aphrodite was looted around the same time as the Hades. The Getty acquired the statue of Aphrodite from Symes in 1988 for $18 million.

Since that statue’s return, experts believe it represents the goddess Persephone or her mother, Demeter, who were worshipped in the ancient city. Persephone and Hades are closely associated in Greek mythology. Hades abducted Persephone at Largo Pergusa, not far from Morgantina, and required her to return to the underworld for several months every year, an explanation for winter.

Several other important looted objects have been returned to the archaeological museum in Morgantina in recent years, including an ancient silver service purchased by the Metropolitan Museum of Art and two marble busts of goddesses by Tempelsman, who also obtained them from Symes.

The head is the latest artifact that the Getty has sent back to Italy following the museum's 2007 agreement with the country's Ministry of Culture. The agreement was made after a protracted legal battle over looted works of art that involved former Getty curator Marion True.

Since then, the Getty has established official ties with various regions of Italy to facilitate cultural exchange. The museum entered a partnership in 2010 with Sicilian officials that covers conservation, exchanges and more.

The head can be seen at the Getty Villa as part of "The Sanctuaries of Demeter and Persephone at Morgantina" until Jan. 21. It will be transferred to the Museo Archeologico in Aidone, Sicily, after the Getty-organized traveling exhibition "Sicily: Art and Invention between Greece and Rome," in which it is also featured.