The sinews of war are infinite money.

This maxim is commonly attributed to Cicero in later quotation tradition as a succinct statement of Roman realpolitik: military success depends on financial resources to pay troops, procure supplies, and sustain campaigns. In the late Roman Republic, Cicero repeatedly confronted the fiscal pressures of war—whether in debates over provincial exactions, emergency levies, or the costs of maintaining armies amid civil conflict. The phrasing circulated widely in early modern political writing as a classical authority for the idea that “money is the nerve/sinew of war,” but the exact Latin form and its placement in Cicero’s surviving works are difficult to pin down with certainty from memory alone.

The image of “sinews” (or “nerves”) suggests what makes a body capable of action: money functions as the connective tissue that turns strategy and manpower into effective force. The point is not merely that war is expensive, but that financial capacity is a decisive strategic factor—armies march, eat, and remain loyal through reliable funding. The adjective “infinite” intensifies the claim: war’s demands expand without clear limit, so a state that cannot generate or access large, continuing revenues will be constrained regardless of courage or generalship. The saying also carries an implicit warning about the political consequences of financing war—taxation, debt, and exploitation.