Ferdinando's foreign policy attempted to free Tuscany from Spanish domination.
After the assassination of Henry III of France in 1589, he supported Henry IV of France in his struggles against the Catholic League.
Ferdinando lent Henry money and encouraged him to convert to Catholicism, which he eventually did.
Ferdinando also used his influence with Pope Clement VIII to get him to accept Henry's conversion.

Henry showed no appreciation for these favors, and Ferdinando let the relationship cool, maintaining his cherished independence.
He supported Philip III of Spain in his campaign in Algeria and Holy Roman Emperor Rudolf II in his against the Turks.
For these undertakings, he found it necessary to raise taxes on his subjects.
He finally obtained the formal investiture of Siena, which his father had conquered.

Ferdinando strengthened the Tuscan fleet, and it saw victories against pirates on the Barbary coast in 1607 and against a superior Turkish fleet the following year.

He also dreamed of a small African empire, and then considered the possibility of a colony in Brazil.
Ferdinando organised an expedition in 1608 under the command of Captain Robert Thornton to northern Brazil and the Amazon river in order to create a colony.
Ferdinando's foreign policy attempted to free Tuscany from Spanish domination. After the assassination of Henry III of France in 1589, he supported Henry IV of France in his struggles against the Catholic League. Ferdinando lent Henry money and encouraged him to convert to Catholicism, which he eventually did. Ferdinando also used his influence with Pope Clement VIII to get him to accept Henry's conversion.
Henry showed no appreciation for these favors, and Ferdinando let the relationship cool, maintaining his cherished independence. He supported Philip III of Spain in his campaign in Algeria and Holy Roman Emperor Rudolf II in his against the Turks. For these undertakings, he found it necessary to raise taxes on his subjects. He finally obtained the formal investiture of Siena, which his father had conquered.
Ferdinando strengthened the Tuscan fleet, and it saw victories against pirates on the Barbary coast in 1607 and against a superior Turkish fleet the following year.
He also dreamed of a small African empire, and then considered the possibility of a colony in Brazil. Ferdinando organised an expedition in 1608 under the command of Captain Robert Thornton to northern Brazil and the Amazon river in order to create a colony.
Ferdinando I de' Medici, Grand Duke of Tuscany