Sotheby's announced Thursday that it is selling the collection on behalf of the New York City-based Hispanic Society of America. The society's founder amassed the collection more than 100 years ago.
The collection includes 50 massive gold coins called Excelentes struck under Ferdinand and Isabella, during the period of Christopher Columbus' expeditions.
Other coins date from the Roman Empire and from the era before Rome when a number of cultures including Celts and Phoenicians inhabited what is now Spain. The Islamic period after the year 711 is also represented.
The coins are being sold as one lot in a sealed bid auction ending March 8.