Before Mussolini's March on Rome in Italy, fascists occupied the headquarters of the Workers' Committee in Trieste in 1921, set it on fire, and attacked representatives of the Raša (Arsa) Mining Trade Union.

Prompted by this event and the exploitative character of the mine owners, the Società Anonima Carbonifera Arsa [it], a general strike of about two thousand miners broke out.

Augmented by the arrival of the peasants from the surrounding countryside, a "red guard" was organized as a security force tasked with maintaining order.

On April 8, 1921 the Italian administration in Istria, responding to requests for intervention from the mine owners, decided to suppress the republic using military force.

[10] Lawyers Edmondo Puecher, Guido Zennaro and Egidio Cerlenizza successfully defended the accused, and the jury issued an acquittal.