"What we have found is an emperor.”
This ancient gold coin proves that a third century Roman emperor thought to be fictional really did exist.
The coin bears the name Sponsian and a portrait of the lost historical figure.
Found more than 300 years ago in Transylvania, the coin was locked away in a museum cupboard after experts decided it was fake.
Now scientists say microscopic scratch marks prove that it was used 2,000 years ago.