Austrian 1765 Maria Theresa Ducat

The 1765 Maria Theresa ducat was struck from gold refined to a fineness of 986/1000, sourced largely from the Habsburg-controlled mines in Hungary.

That purity made it a reliable standard for international trade, even as Europe's currencies fluctuated wildly. The obverse bears the empress's portrait, her hair in an elaborate coiffure that hints at the wig fashions of the day. On the reverse, the imperial double-headed eagle clutches symbols of power.

Mintage numbers for this issue remain uncertain; archives from the Vienna mint suffered losses in later conflicts. What we do know is that these ducats circulated widely, from Vienna to Venice.

Experts sometimes quibble over the date's authenticity, given the empress's long reign. It's like debating the vintage of a well-aged wine—pedantic, but occasionally warranted.