An ancient piece of jewellery known as the Theseus ring and dating from the 15th century BC, has been certified as authentic by Greece's top archaeological council (KAS), the Greek Ministry of Culture said on Wednesday.

Experts at the Democritus Institute had spent more than six months analysing the ring made with 20 grams of gold, which was found in debris at the foot of the Acropolis in Athens.

An archaeologist specialising in ancient Crete, Yannis Sakellarakis, and a member of KAS had argued that it could be a fake.

The KAS, however, backed the opinion of most of the experts and decided to pay €75 000, half the estimated value of the ring, to the ring's owner so it can be put on display at the National Archaeological Museum in Athens.

The signet ring, from the Mycenaean era on Crete, bears a seal engraved with a bull-leaping scene, recalling the Greek myth of Theseus and the minotaur.

According to the owner, the ring was found by her father-in law during expansion work in the 1950s of the museum at the ancient Acropolis site, but he kept it hidden in a chicken run at his country home.

After her father-in-law's death, she declared it to the authorities in order to get an estimate of its value and to sell it to the state.