August Spies  Albert Parsons  Samuel Fielden Carter Harrison III (mayor) John Bonfield (police inspector)

On Monday May 3, speaking to a rally outside a McCormick Harvesting Machine Company plant on the West Side of Chicago, August Spies advised the striking workers to "hold together, to stand by their union, or they would not succeed".

Printed in German and English, the fliers stated that the police had murdered the strikers on behalf of business interests and urged workers to seek justice.

Samuel Fielden spoke to a crowd estimated variously at between 600 and 3,000[22] while standing in an open wagon adjacent to the square on Des Plaines Street.

[23] Paul Avrich, a historian specializing in the study of anarchism, quotes Spies as saying: There seems to prevail the opinion in some quarters that this meeting has been called to inaugurate a riot, hence these warlike preparations on the part of so-called 'law and order.'

Parsons spoke for almost an hour before standing down in favor of the last speaker of the evening, the English-born socialist, anarchist, and labor activist Methodist pastor Rev.

[25] A New York Times article, with the dateline May 4, and headlined "Rioting and Bloodshed in the Streets of Chicago ... Twelve Policemen Dead or Dying", reported that Fielden spoke for 20 minutes, alleging that his words grew "wilder and more violent as he proceeded".

[26] Another New York Times article, headlined "Anarchy's Red Hand," dated May 6, opens with: "The villainous teachings of the Anarchists bore bloody fruit in Chicago tonight and before daylight at least a dozen stalwart men will have laid down their lives as a tribute to the doctrine of Herr Johann Most."

[27] At about 10:30 pm, just as Fielden was finishing his speech, police arrived en masse, marching in formation towards the speakers' wagon, and ordered the rally to disperse.

[26][29] A home-made fragmentation bomb[30][31] was thrown into the path of the advancing police, where it exploded, killing policeman Mathias J. Degan[32] and severely wounding many of the other policemen.

[39] Historian Timothy Messer-Kruse argues that, although it is impossible to rule out lethal friendly fire, several policemen were probably shot by armed protesters.

He alleged that the defendants had experimented with dynamite bombs and accused them of having published what he said was a code word, "Ruhe" ("peace"), in the Arbeiter-Zeitung as a call to arms at Haymarket Square.

Not directly tied to the Haymarket rally, but arrested for their militant radicalism were George Engel, who had been at home playing cards on that day, and Louis Lingg, the hot-headed bomb-maker denounced by his associate Seliger.

Another defendant who had not been present that day was Oscar Neebe, an American-born citizen of German descent who was associated with the Arbeiter-Zeitung and had attempted to revive it in the aftermath of the Haymarket riot.

[58] The prosecution, led by Julius Grinnell, argued that, since the defendants had not actively discouraged the person who had thrown the bomb, they were therefore equally responsible as conspirators.

[50] Schaack concluded, on the basis of interviews, that the anarchists had been experimenting for years with dynamite and other explosives, refining the design of their bombs before coming up with the effective one used at the Haymarket.

The sentencing provoked outrage from labor and workers' movements and their supporters, resulting in protests around the world, and elevating the defendants to the status of martyrs, especially abroad.

[62] In an article datelined May 4, entitled "Anarchy's Red Hand", The New York Times had described the incident as the "bloody fruit" of "the villainous teachings of the Anarchists".

[64] The journalist George Frederic Parsons wrote a piece for The Atlantic Monthly in which he identified the fears of middle-class Americans concerning labor radicalism, and asserted that the workers had only themselves to blame for their troubles.

Witnesses reported that the condemned men did not die immediately when they dropped but strangled to death slowly, a sight which left the spectators visibly shaken.

On June 26, 1893, Illinois governor John Peter Altgeld, the progressive governor of Illinois, himself a German immigrant, signed pardons for Fielden, Neebe, and Schwab,[75] calling them victims of "hysteria, packed juries, and a biased judge" and noting that the state "has never discovered who it was that threw the bomb which killed the policeman, and the evidence does not show any connection whatsoever between the defendants and the man who threw it".

Historian Carl Smith wrote: "The visceral feelings of fear and anger surrounding the trial ruled out anything but the pretense of justice right from the outset.

[85] Historian Nathan Fine points out that trade-union activities continued to show signs of growth and vitality, culminating later in 1886 with the establishment of the Labor Party of Chicago.

[86] Fine observes: The fact is that despite police repression, newspaper incitement to hysteria, and organization of the possessing classes, which followed the throwing of the bomb on May 4, the Chicago wage earners only united their forces and stiffened their resistance.

[96] In 1939, Oscar Neebe's grandson attended the May Day parade in Mexico City and was shown, as his host told him, "how the world shows respect to your grandfather".

Emma Goldman, the activist and political theorist, was attracted to anarchism after reading about the incident and the executions, which she later described as "the events that had inspired my spiritual birth and growth".

[99] Others whose commitment to anarchism, or revolutionary socialism, crystallized as a result of the Haymarket Affair included Voltairine de Cleyre and "Big Bill" Haywood, a founding member of the Industrial Workers of the World.

[125] During the 1950s, construction of the Kennedy Expressway erased about half of the old, run-down market square, and in 1956, the statue was moved to a special platform built for it overlooking the freeway, near its original location.

[123] In 1992, the site of the speakers' wagon was marked by a bronze plaque set into the sidewalk, reading: A decade of strife between labor and industry culminated here in a confrontation that resulted in the tragic death of both workers and policemen.

The planned site was to include an international commemoration wall, sidewalk plaques, a cultural pylon, a seating area, and banners, but construction has not yet begun.