 The territory (it was not even a village, or "oppidum") of Colle was created a city ("civitas").The impulse for the new diocese came from Ferdinando I de' Medici, Grand Duke of Tuscany, as the papal bull and a letter from Ferdinando to the people of Colle indicate.The new bishop, Usimbardo Usimbardi, a Canon of the cathedral of Florence and a personal friend of Duke Ferdinando, was appointed on the same day as the establishment of the diocese.