Vintém 'O-O'– João III Lisbon mint

João III inherited a mint system already strained by the demands of financing the Estado da India, and the vintém — a 20-real coin — became one of the workhorses of everyday Portuguese commerce throughout his reign. The 'O-O' designation identifies a specific countermark applied to earlier vinténs to validate continued circulation, a practice the crown resorted to periodically rather than bearing the full cost of complete recoinage.

Gomes references J3 35 through 38 reflect documented die and countermark variants within this type, not separate issues — a distinction that matters for attribution.