8 Reales - Charles II

Potosí's cob coinage from this period — the macuquinas struck by Charles II — was the subject of one of colonial Spain's most damaging mint scandals. Beginning in the 1640s and uncovered definitively in 1649, assayers and mint officials had been systematically debasing silver intended for royal coinage, skimming fine metal for decades. The fallout reached Madrid and resulted in executions, but the corrupt practices were never fully eradicated, and questions about silver fineness at Potosí persisted well into Charles II's reign.

Charles II himself was the last Habsburg king of Spain, ruling under regency until 1675. His coinage continued to fund an empire already in steep decline.