The unique 339-gram piece has a starting price of 2 million Swiss francs ($2.48 million), the Geneva-based Numismatica Genevensis SA auction house said.

“This coin will certainly break the record of the most expensive European coin of all time,” its director Frank Baldacci told Reuters.

The Centen, or 100 escudos in a former Spanish currency, was made in the central Spanish city of Segovia out of gold brought from conquerors who went to the Americas or “New World”.

It was made as a show of regal wealth and power, equalling many years’ salary, and is the largest in modern European history, auction house founder Alain Baron said.

Lost for several centuries, it turned up in the United States around 1950 where a New York collector bought it before selling it to a Spanish buyer a decade later. It was later auctioned to another collector, whose identity is not public.

“It was truly a royal gift, a regal gift for other kings or queens,” Baron said. “The next owner will in some way have the possibility to be equal to a king since it is a king who gave it to another king.”

There was interest from buyers in the US, Europe and the Middle East looking for a “trophy asset,” as well as institutions, the auction house said.

The current record price for a European coin is a 100-ducat piece once belonging to Ferdinand III of Habsburg that sold for 1.95 million Swiss francs ($2.42 million), Baldacci said.