The four men who led the March on Rome were designated field marshals of the Fascist revolution: Italo Balbo, Emilio De Bono, Cesare Maria De Vecchi, and Michele Bianchi, secretary general of the Partito Nazionale Fascista/National Fascist Party (PNF) until 1923. These four constituted the quadrumvirate. All were “Fascists of the first hour.” Of the four, Italo Balbo was the only one toward whom Benito Mussolini showed a certain wariness. The only institutional function performed by the quadrumvirate was membership by right in the Fascist Grand Council.
Historical Dictionary of Modern Italy. Mark F. Gilbert & K. Robert Nilsson. 2007.