The ancient sculpture, which disappeared from Italy sometime between 1944 and the early 1960s, was handed back to the Italian Ministry of Culture in a ceremony at the German ambassador's residence on Wednesday.
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First unearthed in the 1930s in the city of Fondi between Rome and Naples, it dates from the second century AD and depicts the head and part of the shoulders of a young man.
It has spent the past 55 years in the University of Munster's Archaeological Museum, whose then director acquired it from a private citizen.
Photo: Ministero per i beni e le attività culturali (MiBAC)
Germany offered to return it without being asked, according to Italy's culture minister.
"This is a highly symbolic act," said Alberto Bonisoli, who described it as a sign of the two countries' shared commitment to protecting cultural heritage.
"Italy is not only in the position of reclaiming stolen works of art, but when circumstances demand it, we're among the first to return works belonging to other countries' cultural heritage," the minister declared.
With centuries of art and artefacts strewn all over Italy, many pieces have been lost over the years to thieves, traffickers and natural disasters. Italian police are some of the world's best at hunting down stolen works, with a specialized unit known as the 'Art Squad' devoted to tracking and protecting lost treasures.
But the new owners aren't always keen to give them back. Among the most notable disputes is Italy's ongoing tussle with the Getty Museum in the United States over the Statue of a Victorious Youth – better known as the Getty Bronze – which the American institution refuses to return despite a ruling by Italy's highest court that it was removed from Italy illegally.