Founded in Rome on 7 November 1921, the Party marked the transformation of the paramilitary Fasci Italiani di Combattimento into a more coherent political group (the Fasci di Combattimento had been founded by Mussolini in Milan's Piazza San Sepolcro, on 23 March 1919). The PNF was instrumental in directing and popularizing support for Mussolini's ideology. It was the main agent of the coup d'état attempted as the 28 October 1922 March on Rome (although a parallel agreement between Mussolini and King Victor Emmanuel III was arguably more important).