In the afternoon of September 21, 1864, after clashes between demonstrators and law enforcement had taken place in Turin's Piazza San Carlo in the morning, a crowd of civilians armed with sticks attempted to approach the headquarters of the Ministry of the Interior in Piazza Castello, which was defended by a contingent of carabinieri cadets: the carabinieri fired on the demonstrators, causing 15 casualties.

The events caused the fall of the Minghetti government as well as several official inquiries by parliamentary commissions; however, all those arrested were subject to a general amnesty in February 1865.

In June 1864, taking advantage of rumors about the health of Pope Pius IX and possible uprisings in the Papal States, prime minister Marco Minghetti sent Gioacchino Napoleone Pepoli to the Italian ambassador in Paris, Costantino Nigra, with arrangements to negotiate the withdrawal of French troops from the Holy See's territories.

To reach the agreement, Emperor Napoleon III required a guarantee showing the renunciation of the conquest of Rome, which had been indicated since 1861 by the Italian government as the ideal capital of the kingdom; Pepoli asked if moving the Italian capital from Turin to another city, something already assumed by the government, could provide adequate guarantee; the emperor confirmed that he would certainly sign the agreement with that condition.

He seemed for a few moments somewhat shaken, and then took time to think about it during an absence from Turin.On September 11, 1864, Minghetti informed Minister Menabrea that the king accepted the treaty, moving the capital to Florence for purely strategic reasons.

[7] The dissemination of fragmentary news then led to speculation and accusations against the government; there were even rumors of ceding Piedmontese territory to France.

[8] On September 20, a demonstration was held in the streets of the city with shouts against the relocation of the capital ("Down with the ministry!, Rome or Turin!, Down with the agreement!, Long live Garibaldi!")

"In addition, about 100 people gathered in Piazza Castello to protest with whistles against the headquarters of the Gazzetta di Torino, leaving after a short time without incident.

[11][note 2] The article was in fact compiled, but so poorly that it had the opposite effect, although it interpreted itself far worse than it deserved, thus becoming an incidental cause of the painful events that followed.

The column marched at a brisk pace without uttering a word and without the people against whom they were coming moving away; and in the act the officer grabbed the flag to snatch it out of the hands of those holding it, shouting something unintelligible, which for the aftermath we thought was an order to take up arms and use them; all of a sudden, the guards, having unsheathed their daggers, started to slash that group of people standing on the square – mind you, on the square and not under the porch – running after those who were trying to save themselves by fleeing, and hitting them mercilessly.

We then saw scenes that would make one shudder, among them isolated men beaten and dragged by four or five guards.Twenty-nine people were taken to the police station, including some injured; a new group began to form in front of the building, and the guards came out again with daggers in their fists, but were stopped by their superiors.

Another group of demonstrators, armed with sticks, entered the square and headed for the ministry toward the carabinieri cadets; after a brief uproar, two gunshots were heard, followed by a line of fire aimed at the population.

[26] Reactions to the events of the previous evening An exchange of communications took place between Victor Emmanuel II and Marco Minghetti the morning after the first massacre.

[...] It would be necessary to arrange with the Mayor a deputation to come to Turin and apologize to me, and to recommend some favorable changes that would calm and please the citizens misled by excess of love.

Leave the responsibility for that to General Della Rocca, if you wish.There were a few demonstrations during the day against the printing press of the Turin Gazette, but these were easily dispersed.

[30] A vast cackling gathering, described as consisting largely of drunkards, arrived in the square and began cursing at the carabinieri present and throwing stones at the police headquarters.

[32] The undersigned declares that on the evening of September 22 at 9 o'clock precisely, he was in front of the San Carlo trattoria in the company of a few friends, and was trying to dissuade the few rioters around him, when a trumpet blast was heard and immediately followed by a disorderly discharge made by the Carabinieri cadets who had a moment before emerged from the Police Headquarters.

"[35] Police headquarters of the district of Turin – September 22, 1864 The undersigned requests the town hall to send suitable persons as soon as possible to transport twelve corpses that are in the middle of Piazza San Carlo, as discussed with Count Corsi.

He spoke of the mournful event in Piazza S. Carlo, stigmatizing, in unparliamentary words, the insipience of those who presided over public order, of those who were the cause of the massacre of so many defenseless people, even to the point of having the troops shot among themselves and having poor Colonel Colombini, who has two bullets to his temple, almost killed by his own soldiers.As the current state of affairs cannot last because it is too sad, I urge you and your colleagues to resign.In obedience to Your Majesty's obsequious dispatch I place in your hands my resignation and that of my colleagues, ready to remain in our places until Your Majesty appoints our successors.On the same day, the king commissioned Alfonso La Marmora to form a new government.

On Oct 24, the Chamber appointed a commission of inquiry to determine possible government responsibility, chaired by Carlo Bon Compagni di Mombello and composed of deputies Claudio Sandonnini (secretary), Giuseppe Biancheri, Francesco de Sanctis, Vincenzo Malenchini, Giovanni Morandini, Oreste Regnoli, Giuseppe Robecchi and Giorgio Tamajo.

On the evening of the 27th there was a demonstration, but not by students; there were clashes with the National Guard and 25 participants were arrested, listed as "known to the police, subject to special surveillance, several having recently left prison.

[56] These demonstrations, according to the mayor, were to be attributed "to the lack of work that left a good number of unemployed workers on the pavement due to the cessation of that movement that had manifested itself in the City before the relocation of the Capital.

"[57] On January 29, a court dance party was announced for the following day;[58] in fact, Minister Giovanni Lanza believed that the situation was now calm in Turin and that there would be no incidents.

Even at the risk of a seizure, we will say that on all sides there was universal lamentation that the party was like an insult to Turin; it was said that while the Court, for futile reasons, used to call mourners and suspend all festivities, it was strange that it could not abstain from them when its capital, the city that had been the propugnacle and defense of the dynasty, was still stained with the unavenged blood of so many victims.

It is finally abolished the criminal prosecution for all crimes committed up to the present day by means of the press, which have relation to the facts mentioned in the two previous articles.

A document dated February 9, 1866, from the historical archives of the Ministry of Foreign Affairs (attached to a communication from the Italian consul in Montevideo dated Feb. 13) reports that Giacomo Ramò, captain of the boat Emilia, stated that he had transported from Genoa to Buenos Aires 138 enlisted men for the Argentine government delivered to him by security guards on Oct 14 and 16, 1865; for the 72 embarked on Oct 14 he was reportedly told that "they were part of the Turin uprising of Sept. 21 and 22 and that portions were being extracted from the prisons of Sant'Andrea in Genoa.

Several non-Piedmontese deputies and members of the government were in favor of relocating the capital from Turin because they considered the Piedmontese presence within the public administration excessive.

[64] In publications and newspapers from Turin at the time, the idea of a plan by the president of the Council Marco Minghetti (from Bologna), the minister of the interior Ubaldino Peruzzi (from Florence) and the secretary Silvio Spaventa (from Naples) to provoke riots and to be able to suspend or take away civil liberties was circulated;[65] the presence of provocateurs who would stir up the crowd was mentioned.

In Piazza Castello every member of the Procession, as if moved by an electric wire, lifted their hats as they passed over the mournful site where the blood of September 21 had been shed.

[71] The image given in the National Almanac for 1866 with a funerary stele is to be considered fictional, because in 1865 wreaths were laid on individual graves, and no monument is mentioned in the description.