The family is also featured in Florentine Histories, a book written by Niccolò Machiavelli, where he describes the reign of Pope Pius II, who had allied himself with the Venetians and Prince Vlad Dracula, to wage a war against the Sultan of the Ottoman empire.

[4] In 1220, Engelberto d'Ugo Piccolomini received the fief of Montertari in Val d'Orcia from the Holy Roman Emperor Frederick II as a reward for the services rendered.

[3] They obtained great wealth through trade, and established counting-houses (merchant banks) in Venice, Genoa, Trieste, Aquileia, and in various cities of France and Germany.

But through their riotous political activity, the Piccolominis lost their commercial influence, which passed into the hands of the Florentines, although they retained their palaces, castles and about twenty fiefs, some of which were in the territory of Amalfi, to a great extent.

To seal their ancient genealogy with a legal certification, they commissioned a notary, Alessandro Rocchigiani, to put in order the various sources that disserted the family's origin.