Southern Italy was and remains the poorest part of Italy. When we think of Italians, we are actually thinking about Sicilians and Neapolitans and individuals from points in between. That's where the majority of Italian immigrants to America in the 19th century came from. Northern Italians were much different with their own unique culture and set of traditions. The concept of a certain amount of individual freedom and something of democratic government were well established in Northern Italy from the time of the Italian city-states. The great works of the Renaissance, of Michelangelo, the miracle of Brunelleschi's Dome are all in Northern Italy and Rome. Not Southern Italy.
The ancient lands of Southern Italy - Sicily, Apulia, Calabria, and Campania - have been occupied many times by foreign invaders whose governance of these territories was nothing more than banditry writ large. Local bandits were better than foreign bandits so organized criminal groups such as the mafia got their start and with them came the culture of ‘omerta,’ which translates as "the code of silence." And this code of silence applied to one's dealings with whatever group was officially governing the area which included the House of Savoy on occasion. One said nothing to the authorities about anything. Murder? Arson? Rape? Theft? Retribution for these crimes was expected to be exacted by those wronged or their family and friends. This was Southern Italy’s code of honor, if you can call it that.
If the formal authorities caught you for one of those crimes, not one person would serve as a witness against you. If one did, he or she was murdered by the locals. So the various occupying powers just shot whomever they thought was guilty. Or they didn't care as long as they were left alone. The new Kingdom of Italy and its laws meant nothing. Nor does the Republic of Italy and its laws mean anything now. I doubt anyone would say that the Italian state actually governs Sicily.
Perhaps a useful comparison is this: the Americans and the British have much more in common, both then and now, than Sicilians and Florentines (inhabitants of Florence).
And so over this whole mess presided the Royal House of Savoy and if any of them had any brains, and some of them did, they must have rued the day their dynasty became so greedy that it went along with swallowing up the rest of Italy since nothing but heartache followed unification. Indeed, just keeping order often required the carabinieri and army to fire on crowds of protesters, mainly leftist protesters. This created a bit of animosity toward the Royal House. On 29 July 1900 King Umberto I was assassinated. This was unfortunate since his son, Victor Emmanuel III, was not only a fool but reigned for the next forty-six years.
[Image courtesy of Wikipedia.]