The Florentines were the inhabitants of the Italian city of Florence.
The Leonardo da Vinci hologram became angry at the "foolish Florentines" when they mocked him for having tried (and failed) to fly with his flying machine. Later, da Vinci stated that the Florentines did not deserve his genius, so he had written to the King of France in order to join his court. (VOY: "Concerning Flight")