Consisting of perhaps hundreds of magnificent silver statues, vases, bowls, plates and wine goblets, the hoard may prove to be the largest ancient silver treasure found to date.
The Iranian treasure was found by chance, by villagers in a cave in the north of the country. It was smuggled out overland, probably through Turkey.
The collection - some of which is now in the hands of dealers in Europe and the US - is estimated to be worth between pounds 4m and pounds 8m. However, it is understood that a number of items were seized by the Iranian government.
Where precisely the hoard was found is still a mystery. Some reports suggest that the treasure was discovered near to the southern coast of the Caspian Sea. However, the material is more likely to have come from what used to be the ancient kingdoms of the Manneans in what is now north-west Iran.
The Mannean kingdoms flourished from at least the 10th century BC to the sixth century BC, and many were client states of the mighty Assyrian empire.
The dozens of silver items - some reports say more than 200 - were almost certainly part of a temple treasure.
The treasure was probably stashed away in the cave to prevent it being seized by invaders.
Given the date of the silver items, it is likely that they were hidden at the time of the Assyrian invasions of Mannea in the late eighth century BC or during the Median or nomad Scythian invasions of the mid- seventh century BC.
Looting activities by the Assyrians against enemy temples are well-documented.