Francesca—creator of her own unhappiness
Much of Pierina's personal life bordered on controversy.
The primary antagonist throughout her life was Francesca Salviati who was 2 years younger than Pierina. Francesca came from a prominent family, a branch of the de' Medicis. She was bright, attractive, capable, yet she had a sour disposition and ungenerous spirit that caused people to steer clear of her. In lieu of spending time with friends (she had none), she made it her mission to bring down Pierina who was a beloved young member of Florentine society.
Francesca's envy first reared its sadistic head when she spread a rumor that Pierina was a witch. Fortunately, the citizens of Florence were far beyond superstitious frenzy, and they understood that Pierina's predictions came from her keen intellect and ability to understand human behavior and track cycles and patterns. No one in town was worried that Pierina was a witch. Nonetheless,
Witch!
The first time the inquisitors came to town, they questioned Pierina and not only found her innocent, but stayed for dinner at the family home, enjoying the company, marveling at da Vinci's inventions (a few of which they tried to secure for Spain), and plying Pierina for predictions, as they viewed them fascinating and potentially helpful, not remotely harmful.
In later years, after Francesca had become the new Signora de' Medici, she again sent for the inquisitors, citing all manner of outlandish lies and blaming them on Pierina. The representatives who showed up in Florence looking for Pierina were brutal and hellbent on making their trip worth their while. The meant to try, convict, and execute Pierina before returning to Spain.
Ottaviano was able to get word to Pierina in Tuscany, and she fled before the inquisitors arrived, staying away for several months to avoid detection. There is no information on where she went.
Thief!
He is famed for his book Les Prophéties, comprised 942 poetic quatrains reputed to predict future events. Being around Pierina's age, he was well-acquainted with her prognostications, and even met her on two occasions. Both times he plied her with questions and requests for predictions.
When his book came out, the grapevine was a buzz with claims that Nostradamus had taken Pierina's prognostications and thrown in a whole bunch of fluffy predictions of his own around them to make it look like he had was a prolific seer. Nostradamus was so embarrassed by the rumors, that he accused Pierina of stealing his ideas, even though there was no evidence to support his claims. When he was unable to prove her thievery, he jumped on the bandwagon, decrying her as a witch.
The witch stigma would follow Pierina throughout her life. When asked if she was indeed a witch, she said,
"Alas, I am not. I am not disciplined enough to take up that noble art of helping and healing. But I applaud all who do. One day, perhaps."