Although it is not clear where they were actually established, they first came to prominence in the Kingdom of Naples during the Napoleonic wars. Although some of the society's documents claimed that it had origins in medieval France, and that its progenitors were under the sponsorship of Francis I of France during the sixteenth century, this claim cannot be verified by outside sources. Although a plethora of theories has been advanced as to the origins of the Carbonari, the organization most likely emerged as an offshoot of Freemasonry, as part of the spread of liberal ideas from the French Revolution. They first became influential in the Kingdom of Naples (under the control of Joachim Murat) and in the Papal States, the most resistant opposition to the "Risorgimento".