Two million euros is the price a single coin is expected to reach when the collection of which it forms a part goes up for auction in Barcelona on Wednesday and Thursday.

The collection is a unique set of 2,200 gold coins which has attracted collectors from all over the world to the auction being held in the Catalonian capital.

Interestingly, the collection is being sold by an American who inherited it from a Basque ancestor who had emigrated to the US. The star piece is without doubt a gold coin known as a Centén (due to its worth of 100 reales, an antiquated Spanish currency).

The coin was minted in Segovia in 1609 by order of the then monarch Philip III. It is the biggest gold coin ever to be minted in Spain and was the first of its kind in Europe.

The gold Centen goes up for sale on Thursday at a starting price of 800,000 euros. It is estimated that it will reach a final value of 2 million euros.