1 Bolognino

Siena struck bolognini throughout the sixteenth century as the republic's financial position deteriorated under repeated military pressure from Florence and its Habsburg allies. By 1550, the city was barely two years from the siege that would effectively end its independence — the Florentine-Imperial blockade of 1553–1555 that reduced the population by roughly two-thirds and delivered the republic to Cosimo I de' Medici.

The billon content of late Sienese issues reflects progressive debasement under fiscal strain. MIR 563 is well-documented in CNI XI with sufficient die variation to suggest sustained output despite the circumstances.