[1] After obtaining a doctorate in law from the University of Pisa, Picchena pursued a long career in diplomacy on behalf of the Medici family.
He entered the service of Grand Duke Francesco I de' Medici by an introduction from Belisario Vinta, then a First Secretary of Tuscany.
Accused of the assassination of Florentine rebels like Troilo Orsini who had sought refuge with the Queen Mother, Catherine de' Medici, Picchena was arrested.
They feared his true motive was to enlist soldiers in support of Henry of Navarre, the rightful heir to the French throne, who remained a Protestant at the time.
Upon completing the mission, the Grand Duke selected Franz Sebastian von Beroldingen as his new informant and Rudolf Reding as the colonel responsible for troop recruitment in the event of war.
In 1607, he was again entrusted with a diplomatic mission, traveling to Rome to discuss the deployment of fleets to the Levant with Pope Paul V. His involvement in Florentine politics continued with his appointment as one of the "Twelve Good Men" (sort of a jury in Florence) in 1610.
Cosimo II had decreed that upon his death, his mother Christina of Lorraine and wife Maria Maddalena of Austria would become guardians and regents.
According to Riguccio Galluzzi Picchena displayed "a proud disdain for others' smallness" due to his difficult temperament, and neglected to cultivate relationships at court, relying solely on the appreciation of his "long and faithful service" to the ruling family.
In contrast, Cioli skillfully built strong relationships with the Grand Duchesses and soon became the "arbiter of the Regency," effectively pushing Picchena out of the court's inner circle.
His other works include: Picchena maintained correspondence with Galileo Galilei, accompanying him to Rome in 1615[8] and was a friend of Giovanni Battista Strozzi, Lorenzo Pignoria, and other scholars who flourished around the Medici court at that time.