The term was later applied to a similar group serving the British Union of Fascists before the war and to members of an Atheist quasi-political organization in India.
Inspired by Giuseppe Garibaldi's Redshirts, the Fascist Blackshirts were organized by Benito Mussolini as the military tool of his political movement. The founders of the paramilitary groups were nationalist intellectuals, former army officers or members of the special corp Arditi, young landowners opposing peasants' and country labourers' unions. Their methods became harsher as Mussolini's power grew, and they used violence, torture, intimidation, and murder against Mussolini's opponents. One of their distinctive techniques was force-feeding castor oil.
The ethos and sometimes the uniform were later copied by others who shared Mussolini's political ideas, including Adolf Hitler in Nazi Germany, who issued brown shirts to the "Storm Troops" (Sturmabteilung) and black uniforms to the "Shield Squadron" (Schutzstaffel, also colloquially known as "Blackshirts", because they wore black suit-like tunics with brown shirts), Sir Oswald Mosley in the United Kingdom (whose British Union of Fascists were also known as the "Blackshirts"), William Dudley Pelley in the United States (Silver Legion of America or "Silver Shirts"), in Mexico the Camisas Doradas or "Golden Shirts", Plínio Salgado in Brazil (whose followers wore green shirts), and Eoin O'Duffy in the Irish Free State (Army Comrades Association or "Blueshirts"). "Blueshirts" can also refer to Canadian fascists belonging to the Canadian National Socialist Unity Party.
The Blackshirts were established as the squadristi in 1919 and consisted of many disgruntled former soldiers which may have numbered 200,000 by the time of Mussolini's March on Rome from October 27 to October 29, 1922. In 1922 the squadristi were reorganized into the milizia and formed numerous bandiere, and on 1 February 1923 the Blackshirts became the Volunteer Militia for National Security (Milizia Volontaria per la Sicurezza Nazionale, or MVSN), which lasted until the Italian Armistice in 1943. The Italian Social Republic, located in the areas of northern Italy occupied by Germany, reformed the MVSN into the Republican National Guard (Guardia Nazionale Repubblicana, or GNR).
These units were also organized on the triangular principle as follows:
The first six Divisions were sent to Ethiopia and participated in the war. The 7th CCNN Division "Cirene" was never deployed overseas or even fully equipped before it was disbanded.
Organization of 1935 Blackshirts Divisions:
The Blackshirts Rifle Battalions had three rifle companies but no MMG company. The rifle companies had three platoons (three squads with one LMG each). Each Legion had a MMG company with four platoons of three weapons each (plus two spare ones). The Blackshirts replacements battalions were organized as the Blackshirts Rifle Battalions, but its platoon were overstrength (60 men each) and with only 1 x LMG in each platoon.
The 3rd CCNN Division was disbanded and consolidated with the 2nd CCNN Division in April 1937 after the Battle of Guadalajara. After the northern campaigns in October 1937, the 2nd CCNN Division was consolidated with the 1st CCNN and renamed the XXIII de Marzo Division "Llamas Negras".
Mussolini also pushed through plans to raise 142 MVSN combat battalions of 650 men each to provide a Gruppo di Assalto to each army division. These Gruppi consisted of two cohorts (each of three centurie of 3 manipoli of 2 squadre each) plus Gruppo Supporto company of two heavy machine gun manipoli (with three HMG each) and two 81 mm mortar manipoli (with 3 Mortars each).
Later 41 Mobile groups were raised to become the third regiment in Italian Army divisions as it was determined through operational experience that the Italian arm's binary divisions were too small in both manpower and heavy equipment. These mobile groups suffered heavy casualties due to being undermanned, under equipped and under trained. The three divisions were destroyed in combat in North Africa. The MVSN fought in every theater where Italy did.
Mussolini as Comandante Generale was made Primo Caporale Onorario (First Honorary Corporal) in 1935 and Adolf Hitler was made Caporale Onorario (Honorary Corporal) in 1937. All other ranks closely approximated those of the old Roman army as follows: