It was the first climax of fascist violence in South Tyrol, a German-speaking province that was annexed by Italy after World War I.
On 24 April 1921, a referendum was held in the part of Tyrol still belonging to Austria regarding the Anschluss to the German Reich.
The fascists, who at that time were a paramilitary group involved in thuggery throughout Italy, considered the coincidental opening of the Bozen Spring Fair on the same day as a provocation connected with the plebiscite.
During the traditional costume procession, the fascists attacked the participants and spectators with clubs, pistols and hand grenades.
[1] The Italian military intervened only to escort the aggressors to the railway station, where they were able to leave unharmed.