The problem of brigandage is explained in the book Heroes and Brigands by the southern Italian historian and politician Francesco Saverio Nitti, outlining that brigandage was endemic in Southern Italy, since the Bourbons themselves relied on it as their military agent.[34] Unlike Southern Italy, there was little brigandage in the other annexed states of northern and central Italy, like the Kingdom of Lombardy-Venetia, the Duchy of Parma, the Duchy of Modena, the Grand Duchy of Tuscany and the Papal States, because the situation of Southern Italy was different, owing to the previous centuries of history.