4 Reales - Felipe III

Felipe III's reign saw the Mexico City mint operating under the assayer Antonio Morales for much of this period, whose "A" mark appears on surviving pieces. These cob-style macuquinas were cut from silver bar stock and hammered between dies with no effort made to regularize the planchet, which is why no two examples share an identical shape. The silver itself came overwhelmingly from Potosí and Zacatecas, moving through a colonial assay system riddled with fraud — the viceroy's inspectors periodically discovered underweight shipments shaved by corrupt mint officials.

A major reassay scandal at the Mexico City mint broke in 1618, implicating several assayers in systematic short-weighting of cobs destined for transatlantic shipment.