On the winter morning of Sunday, 28 June 1896, over fifty delegates gathered in the main hall of a building owned by a German socialist association in downtown Buenos Aires. On the stage were ‘the red flags of trade unions and political groups; on the side walls, banners with the names of the big men of socialism’. Dozens of militants and sympathizers, among them a few women, occupied the galleries that surrounded the space reserved for the delegates, all of whom were men. After appointing a provisional committee, which approved some formalities and read a series of telegrams from the interior provinces, the delegates approved the reports of the auditing committee and started discussing the draft statutes and programme of a new organization. On the evening of the following day, after cheerfully singing Filippo Turati’s Inno dei Lavoratori, the delegates closed the congress that had officially constituted the Socialist Party of Argentina (hereafter, PS).1