Ferdinand and Isabella Ducat

The most intriguing thing about Ferdinand and Isabella's ducat is that it circulated during the very years their sponsorship bankrolled Christopher Columbus's voyages, turning Spanish gold into New World legends.

These gold coins, struck from about 1479 to 1516 in Seville and other mints, featured the monarchs' conjoined arms on one side—a blunt nod to Spain's messy unification under their rule. We know the ducat weighed around 3.5 grams, pure enough to dazzle merchants from Antwerp to Alexandria, but exact designs varied by year, with some showing a cross potent that hinted at the era's religious fervor. Mintage figures? Lost to time, likely in one of Europe's countless archival blazes.

One oddity: Collectors sometimes mistake these for Venetian ducats, given the name's Italian roots—Spain's version was more a local adaptation than a copy.