320 Réis - Maria I Lisbon and Rio de Janeiro Mints

Maria I's 320 réis occupied an awkward monetary position in late colonial Brazil — large enough to matter in daily commerce but frequently underweight due to the Rio de Janeiro mint's inconsistent striking practices, which generated persistent complaints from Lisbon throughout the 1790s. The two mints produced coins of nominally identical type but detectably different character, and period merchants occasionally refused Rio-struck pieces on suspicion of short weight.

Maria herself was declared mentally incapacitated in 1792, leaving her son João as regent, yet coinage continued under her name until well past the turn of the century.