1 Real - Carlos III

Carlos III's monetary reform of 1772 forced Potosí — one of the hemisphere's oldest and most prolific mints — to abandon the cob coinage (macuquina) that had been produced there since 1574 in favor of milled portrait coinage. The transition was administratively brutal; assayers who had spent careers on cob production had to be retrained or replaced, and early milled output from Potosí lagged behind Lima in consistency as a result.

Potosí sat at over 4,000 meters elevation, and the chronic labor shortages at that altitude plagued the mint's new mechanized presses throughout this entire emission window.