On the 25th of August 1891 the workers of Elvetica, a mechanical factory of Milan, decided to call a strike. The protest expanded quickly in a few days and the 30th of August the general strike of the Milanese mechanical labour force was declared. On order from the prefect, Giovanni Codronchi Argeli, more than 1500 soldiers were employed in public security duties. The prefectorial documents, kept in the archive of Giovanni Codronchi Argeli in the municipal library of Imola, and those of the police headquarters of Milan, found in the Archivio di Stato of Milan, have enabled the author the possibility to analyse the relationship between civil and military authorities. In fact, the collaboration between the Prefettura and the head of the III Corpo d’Armata was difficult and their disagreements often caused confusions and incomprehension.
Keywords: Liberal age, Milan, army, strike, police, public order