THESSALONIKI, Greece (AP) ― A Swiss court has ordered the confiscation of a very rare ancient silver coin that was allegedly illegally excavated in northern Greece and sold at auction in Switzerland, Greek and Swiss officials say.

The lawyer representing Greece in the case said Thursday that the ruling in October opens the way for the early 5th century B.C. coin’s return to Greece. The debt-crippled country’s rich cultural heritage has long suffered depredations from antiquities smugglers supplying a lucrative international market.

“The coin was treated in the Swiss court ruling as a product of criminal activity that was illegally exported from our country and was then illegally offered (for sale) abroad,’’ Ilias Bisias told the Associated Press.

Greek authorities were officially notified of the ruling this week.

Swiss prosecutors said the coin has been confiscated while they await a legally binding verdict on the circumstances of its discovery from Greece, which regards all its antiquities as state property.

The high-denomination octadrachm ― or eight-drachma ― coin was struck by a little-known Thracian ruler named Mosses around 480 B.C., the time of the second failed Persian invasion of Greece.

Thessaloniki University professor of archaeology Michalis Tiverios said examples of Mosses’ currency are very rare.

“There are very few coins struck in his name,’’ Tiverios said. “Octadrachms were heavy coins used for transactions abroad, usually for mercenaries’ wages, which is why they are very rarely found in Greece.’’

After allegedly changing hands through a number of offshore companies, according to Greek authorities, the coin was sold in 2009 to an unidentified collector for 100,000 Swiss francs ($106,000). It was then provisionally seized following a Greek request.

Authorities in northern Greece have pressed charges of antiquities theft in the case, although no suspects have yet been named. The Swiss court decision did not identify the seller of the coin at the auction.

In recent years, Greece has secured the return of important illegally excavated antiquities from foreign museums and collections, including the J. Paul Getty Museum in Los Angeles. It has waged a long and unsuccessful battle against the British Museum in London to wrest back the Elgin collection of sculptures, taken from the ancient Parthenon temple on the Acropolis 200 years ago.