A courageous resistance was not enough to save the ancient republic of Siena from the allied armies of Emperor Charles V and the Florentine Duke Cosimo de’ Medici, who, after a long war, in 1557 was awarded the ancient state of Siena as a feudal domain. The Sienese were able to maintain some of their ancient magistracies, which had governed the republic for centuries, and their request to allow the Monte Pio to resume activity was also granted; on 14 October 1568, it was given a new charter similar to that of Florence’s Monte di Pietà. The Monte Pio’s account books bear witness to the progressive development of agricultural and land credit and interest-bearing loans.
In 1580, when it assumed the task of collection agency for the Ufficio dell’Abbondanza (the food authority), the Monte Pio confirmed its role as a public bank. The conviction that the charitable works of the Monte Pio had to be expanded led the citizens of Siena to request the creation of a new credit institution that could furnish financial support to the city’s faltering economy. In particular, the new bank would assist the farmers and livestock raisers, as well as some city institutions, permitting also forms of deposit of private capital.
The Grand Duke granted the request, but on the condition that the new bank be guaranteed by a lien on income from the public pasture lands in the Maremma. In 1624, then, the new institution was founded, which was to be managed by eight citizens belonging to the nobility. The revenues from the pasture lands in Maremma, called the “Dogana dei Paschi (from which the name "Monte dei Paschi" derives), were divided into portions worth 100 scudi each, to be issued in the form of bonds guaranteeing an annual return of 5%.
