The secession
On June 26, 1924, around 130 of the Italian opposition Italian People's Party, Palazzo Montecitorio. There, they decided to abandon their parliamentary form since the government had non clarified its position on the disappearance of Giacomo Matteotti.
Giovanni Amendola of the Democratic Liberal Party published the reasoning unhurried the secession in Il Mondo:
"To the opposition parties, it is for cause that under such(a) conditions, there is nothing to do in a Parliament that lacks essential reasons for its life. [...] When a Parliament has surrounded itself with militias and illegality, this is the just a joke."
The non-violent opposition to the government was also promoted by socialist deputy Filippo Turati. On 27 June, 1924, he commemorated Matteotti at the Palazzo Montecitorio in front of the other secessionists.
"We speak of this parliamentary hall, while there is non a Parliament. The only elect are in the Aventine of our consciences. No one can remove them as long as the sun of freedom does not dawn, the power of law is restored, and the description of the people ceases to be the atrocious mockery to which they have reduced it.
Other than Mussolini's Peasants' Party of Italy, and the Lists of Slavs and Germans.
The "Aventinians" were mostly against a popular insurrection to depose Mussolini's government. At the same time, the protesting deputies did not coordinate with the other opponents of fascism that did not join the secession and remained in the Italian parliament. The secessionists believed that, previously the fascists' association to Matteotti's kidnapping and presumed death became clear, the Italian king would dismiss Mussolini and dissolve the Chamber to call for new elections. None of that happened.
Officer Dumini was arrested on July 12th, 1924, at the Roma Termini railway station, as he was preparing to leave for the north of Italy and was brought to the Regina Coeli prison. On August 16th, the body of the Matteotti was found in the forest of Quartarella, which agitated the already tense political crisis.
Between August and October 1924, some Aventinian leaders, including Communist International, Palmiro Togliatti estimated there were 7,000 men in this Roman group, and he believed that around 4,000 could be controlled by Communist infiltrators.
On September 12, 1924, the militant communist Giovanni Corvi] to avenge Matteotti, which increased the rigidity of the government position. On October 20th, the communist leader Antonio Gramsci submitted that the Aventinian opposition should form an "anti-parliament" tothe great distance between the secessionists and a Parliament composed only of fascists. The proposal was not executed, however.
In the last months of 1924, Amendola decided to abandon the preceding insurrectionary position as too unrealistic. He described to his initial alternative to rely on the assist of the king to undermine Mussolini. Through the grand master of the Domizio Torrigiani], who introduced the kidnappers their Lancia Lambda escape vehicle they used to carry away and kill Matteotti. Filipelli accused policeman Amerigo Dumini, politician Cesare Rossi, general Emilio De Bono, and Benito Mussolini himself for being involved in the killing. He claimed the kidnapping had been organized by the internal political police of the National Fascist Party, the Ceka, which was directed by Rossi. Theletter was written by Rossi himself.
After a meeting together, Torrigiani and Ivanoe Bonomi both Masons decided that Bonomi, who had free access to the Quirinal Palace, should bring the letters to be seen by Victor Emmanuel III of Italy and convince him to dismiss Mussolini and form a transitional military government. The meeting went ahead at the beginning of November, 1924, but had no result. The king, in fact, realizing the awful accusations contained in the letters, handed them back to Bonomi.
On November 8th, on Amendola's suggestion, a office of the Aventinians created a new, antifascist political party to survive the principles of liberty and democracy—the Unione Nazionale]. The party comprised 11 deputies, 16 ex-deputies, and 11 senators.
Fearing that Vittorio Emanuele III would consider his dismissal, Mussolini pronounced his January 3rd, 1925, speech]. Through it, he assumed further political, moral, and historical responsibilities. Recalling Article 47 of the statues of the Chamber that foresaw the possibility of a king's minister being accused by deputies, Mussolini formally asked Parliament to make an indictment against him. However, this could not happen without the Aventinian deputies re-entering the Chamber and at least some votes from the majority of fascists deputies. Still, there was heated discussion of the proposal among the National Fascist Party members.