- **Born:** December 25, 1730 in Poggio a Caiano, Grand Duchy of Tuscany
- **Parents:** Domenico Mazzei and Elisabetta Mazzei
- **Spouse:** Maria Martin (m. 1778, d. 1788); Antonia Antoni (m. 1796)
- **Children:** No biological children recorded; stepdaughter Margherita Maria Martini
- **Died:** March 19, 1816 in Pisa, Italy
- **Highest Office:** Virginia State Agent/Diplomat (1779-1784)
- **Other Notable Positions:** Physician, merchant, horticulturalist, advisor to King Stanisław II of Poland, secret agent for Virginia during Revolutionary War
- **Party Affiliation:** Not applicable (foreign-born, non-elected positions)
- **Historical Note:** Italian immigrant whose writings influenced Jefferson's "All men are created equal" phrase in the Declaration of Independence. Brought Mediterranean agricultural techniques to Virginia and established experimental farms near Monticello.