Historiography of the May Revolution
Historiographical studies of the May Revolution started in the second half of the 19th century in Argentina and have extended to modern day. All historiographical perspectives agree in considering the May Revolution as the turning point that gave birth to the modern nation of Argentina, and that the Revolution was unavoidable in 1810. The main topics of disagreement between Argentine historians are the specific weight of the diverse causes of the May Revolution, who were the leaders of it among the different involved parties, whenever there was popular support for it or not, and whenever the loyalty to the captive Spanish king Ferdinand VII was real or an elaborate masquerade to conceal pro-independence purposes.
May Day riots of 1919
The previous year, Eugene Debs's Federal Court trial was held in Cleveland, and Charles Ruthenberg's Socialist Party chose to hold a march which would both protest Debs' imprisonment as well as help promote Ruthenberg's own candidacy for mayor of Cleveland. The procession consisted of 32 groups divided into four units, each holding a Socialist flag and an American flag at its head. Although the cause of the riots is disputed, repeated demands by the police and army personnel that the marchers relinquish their flags reportedly became a flashpoint.