In the 17th century, two Piccolomini brothers, from the
Modanella branch, were about to make a large family tree of the family. 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. Evidently the fascination of myth, mixed with the reverence due to the illustrious patrons, instead of eliminating the legendary components ended up increasing them.
Horatius Cocles was indicated with certainty, by the zealous notary, as the new progenitor of the family. Undoubtedly some coincidences arouse astonishment. Indeed, in the column that adorned the
Campidoglio, his enterprise, was a
coat of arms identical to that of the Sienese family, stood out carved in the
shield of the
ancient Roman. Once attached to Horace, the Piccolomini lineage had, in ancient Rome, the name of Parenzi, and from there one of its members chose the
Sienese colony as his new residence, became
Podestà (chief magistrate), and abandoned his name, Chiaramontese, and changed it to Piccholuomo. The civil discords that agitated
Rome in those times favored Siena because of their previous affiliation with the members of the
Horatia gens, of which Chiaramontese belonged to. Having left from his homeland in Rome and also his surname, he came to live in the jurisdiction of Siena, and just as it is customary for men from one city when they move to another to take a different name from the usage of their native country, so it happened, Rocchigiani explained, that the Roman exile named Chiaramontese, took on in his new homeland the nickname Piccoluomo (Piccholuomo) from which the surname Piccolomini was later derived. The Piccolominis also descended from a certain Iulius Piccolomini Amideis, a member of the
Amidei family, who was also of Roman descent.
Pope Pius II, his full name being Enea Silvio Bartolomeo Piccolomini, was named in relation to his Roman ancestry and refers to
Aeneas Silvius, King of
Alba Longa, from which the
Amideis also claimed descent through the
gens Julia. ==Prominent family members==