Abstract. The economic strength of early modern Rome consisted essentially in its financial opportunities. At the opening of the seventeenth century, one of the most stable long-term public debts was in place there, with a lively secondary market fostered by bankers, prominent aristocrats, and a broad group of small investors extending all over Italy. Debt instruments (luoghi) accompanied several other forms of loans and revenues, whose opportunities were well exploited by noble Roman families and which were backed and facilitated by several private banking houses and two publicly supported banks (Banco di Santo Spirito and Monte di Pietà, although the latter had charitable functions). This well-established and stable financial setting was also prepared to countenance, among other things, the lavish spending of Roman aristocrats and to permit the richest of them a nearly infinite reserve of credit.