After Southern Italy became part of a new, national state in 1860, its financial sector was radically transformed under Piedmontese influence. This article challenges the conventional wisdom that the aggressive penetration of a Northern credit institution, the future Bank of Italy, into the South following unification harmed the local banking system and highlights instead its transformative role in modernising and deepening regional credit markets. On the basis of new statistics, banking and political records, this contribution shows that the introduction of ‘foreign’ banking from Northern Italy under the auspices of a national, constitutional government resulted in a financial revolution and a democratisation of credit supply to the advantage of the whole South. Public banking under the Bourbons had privileged the needs of an absolute government over those of the private economy and of the capital city over those of the rest of the country, retarding financial development. Credit undersupply and regional fragmentation could only be overcome through the integration of the South within a larger Italian market, in which, however, the lion's share went to a predominantly Northern institution.