Tunis: Tunisia will return the Mask of Gorgon, a Roman-era artefact stolen from Algeria in the 1990s and found at the home of the ousted president’s son-in-law, the culture ministry said on Thursday.

The white marble sculpture of the Medusa’s head will be returned on Monday to the Algerian cultural minister Khalida Toumi at a ceremony in Tunis, a ministry spokeswoman told AFP.

The mask, which is around a metre high and weighs 320 kilogrammes, was stolen from the archaeological site of a major Roman city, Hippo Regius, in northeastern Algeria.

It was among 164 archaeological items found in the house of Sakher Al Materi, who married Zine Al Abidine Bin Ali’s eldest daughter and was long seen as a possible successor.

The artefacts were shown in a television programme broadcast after the Tunisian strongman’s ouster in the January 2011 uprising, and the mask was recognised by a former director of the museum in the Algerian city of Annaba, where the Roman site lies.

Its authenticity was confirmed in 2012 by a group of experts sent to Tunisia by Algeria’s cultural ministry.

Tunisia’s government had promised in 2012 that it would be returned to Algeria “after the completion of legal procedures”.

The marble sculpture was being held by the Tunisian authorities as evidence in a case against Materi for trafficking archaeological artefacts.

The ex-dictator’s son-in-law, who has already been convicted in absentia to 16 years in prison and fined 97 million dinars ($61 million, Dh224 million) for corruption and property fraud, sought asylum in the Seychelles in February 2013.

Authorities in the Indian Ocean archipelago said last week that they would allow him to stay for another 12 months.