...X. was born in Tuscany. He studied medicine in Florence and practiced it for several years before moving to London to take up a mercantile career as an importer. While in London he met Benjamin Franklin and Thomas Adams. They convinced him to undertake his next venture.
In 1773 he led a group of Italians who came to Virginia to introduce the cultivation of vineyards, olives, and other Mediterranean fruit. X. became a neighbor and friend of Jefferson. They started what became the first commercial vineyard in Virginia. They shared an interest in politics.
...The doctrine "All men are created equal" incorporated into the Declaration of Independence, was paraphrased from the writing of X. This phrase appears in X's own hand, written in Italian, several years prior to the writing of the Declaration. X. and Jefferson often exchanged ideas about true liberty and freedom.
In 1779, X. returned to Italy as a secret agent for the state of Virginia. He purchased and shipped arms to them until 1783. After briefly visiting the United States again in 1785, X. travelled throughout Europe promoting Republican ideals. He wrote a political history of the American Revolution, "Recherches historiques et politiques sur les Etats-Unis de l'Amerique septentrionale", and published it in Paris in 1788. After its publication X. became an unofficial roving ambassador in Europe for American ideas and institutions.
While in the Polish-Lithuanian Commonwealth he became attached as a Privy Councilor at the court of King Stanislaus II. The king appointed him as Polish representative in Paris, where he again met Jefferson.
After Poland was partitioned between Russia and Prussia in 1795, X. was given a pension by the Russian crown. He later spent more time in France and became active in the politics of the French Revolution under the Directorate. When Napoleon overthrew that government X. returned to Pisa, Italy.
He died there in 1816.
http://en.wikipedia.org/wiki/Philip_Mazzei