4 Reales

Peru's 4 reales of this period circulated during a decade when the country's silver output from Cerro de Pasco was substantial but increasingly under pressure from political instability and the rise of competing monetary systems. The confederation wars of the late 1830s had disrupted mint operations severely, and this issue reflects the recovery of Lima's Casa de Moneda under more stable republican governance.

KM#151a distinguishes the .903 fineness from the earlier .903+ assay standard — a subtle but cataloged shift tied to fluctuating refining practices at Lima rather than any formal legislative change.