Finally! An American labor history question! They're like unicorns on here.

I'll tl;dr this up here: we will never really know who threw the bomb, but there are several theories out there. Most likely it was one of the people assembled at the Haymarket meeting, but it's possible it could have been an agent provocateur named Rudolph Schnaubelt in the employment of the police or business owners. Please read on if you would like to get a thorough understand of what happened at the Haymarket and the repercussions it had on the American labor movement because if your high school and college 101 American history courses were anything like mine, you learned nearly nothing about labor history in America.

First of all, to summarize what happened at the Haymarket and why there was an assembly there in the first place, we need to start a few years before Haymarket to understand why it was such a seminal moment for the American labor movement and why it would be memorialized. A major goal of American labor unions was for work places to adopt an 8 hour work day. The slogan was "8 hours for work, 8 hours for sleep, and 8 hours for what we will". At that point the average work day was 10-14 hours depending on the industry in which you were employed (though it could get as high as 16). At first labor organizations tried to get legislation passed in cities that would limit the work day to 8 hours, but their victories were limited under that strategy and labor leaders began to call for general strikes to attain their goal. At the general convention in 1884, the Federation of Organized Trades and Labor Unions (FOTLU) resolved that "eight hours shall constitute a legal day's labor from and after May 1, 1886" and they called for a nationwide general strike to enforce their resolution. Now, it's important to realize that not all unions were in lock step with each other over this strategy. The leadership of one of the largest labor organizations, the Knights of Labor (KoL), tried to discourage their members from committing to the resolution, but the members enthusiastically supported it. As different KoL assemblies across the US adopted the 8 hour platform, new membership surged from 110,000 in 1885 to 750,000 in 1886. This was partially due to the inclusiveness of the KoL. Groups who had been excluded from many of the major unions like women, African-Americans, Chinese, and Latinos were welcomed; it also welcomed the "producing classes"- not just wage earners, but housewives, farmers, doctors, clergymen, and other professionals. But I digress... As the movement picked up steam into the spring of 1886, more conservative unions, such as the American Federation of Labor (AFL), even began to call for a general strike on May 1 for 8 hours where ever establishments refused to honor labor's demands.

While the actual bombing took place on May 4, the strikes and rallies themselves began on May 1 with speeches and marches planned for several days thereafter. Nationwide, 350,000 workers in 11,562 establishments went on strike. In Chicago, 65,000 strikers staged weekend rallies and parades and 45,000 workers were granted a permanent 8 hour workday by their employers to prevent them from striking (hey, it worked!). The general strike brought business in Chicago to a sudden stop. The railroads took the biggest hit, to the ire of shipping owners. Chicago was one of the major railroad crossroads of the United States. Farmers and ranchers from the West shipped goods to be sold in the East, while the East shipped shipped manufactured goods and textiles West. Every railroad in Chicago stopped running and wouldn't be back up until the general strike and rallies had finished. Rail owners simply couldn't afford for their cars to sit idle. Now, businessmen didn't just take this laying down, nor had they too not prepared for the events planned on May 1. The state militia had been called up and the police were put on notice. Business owners and state/city politicians had a long history of using the police, militia, private security ( Pinkertons), and even deputized Chicago residents to break up labor strikes and rallies. Probably the biggest foreshadowing of days to come was an article put out by the Chicago Mail on May 1 that specifically named August Spies and Albert Parsons, two anarchist labor leaders who would later be arrested and hung for the bombing, as men to be watched for suspicious activity. "Keep them in view. Hold them personally responsible for any trouble that occurs. Make examples of them if trouble occurs". Chilling, frankly, considering their fate.

So now we get to the first incident of the May Day strikes in Chicago. Strikers and sympathizers were assembled in front of the McCormick Harvester Works on May 3, to protest against the scabs the company had hired to break the weeks long strike at the job site. Nell Irving Painter in Standing at Armageddon notes that strikers from the general strike and the parades descended upon the already ongoing strike, so there were literally thousands of people (we don't have an accurate number) assembled in front of the McCormick Harvester Works. This eventually turned into a fight between strikers and scabs, which in turn lead to the police being called to break it up and maintain order. Depending on the source you read, police either fired into the crowd or fired at strikers fleeing the police- with so many people there, it could have been both. In the end, 4 people were killed and dozens were wounded (I'll see if I can find the exact number).

That evening, anarchist leaders of the International Working People's Association (IWPA), including Spies and Parsons, called a mass meeting to protest police brutality to take place the next day in Haymarket Square. They circulated flyers (in English and German) encouraging strikers to "Arm Yourselves and Appear in Full Force". The next evening 2,000-3,000 people assembled in Haymarket Square to listen to various labor leaders condemn the actions of the police. It had rained lightly throughout the meeting, so the crowd had dwindled down to around 300 people by the time it was almost over. 180 policemen arrived near the end, ordered the crowd to disperse, and approached the speaker's platform. While the labor organizers were explaining that they were almost finished, a bomb exploded in the police formation. The police immediately fired into the crowd for 2 or 3 minutes, who fled in a panic. When the dust settled, 66 policemen were injured, 1 died immediately, and 7 more from their wounds a few days later (it should be noted that 60 police officers were wounded by friendly fire, not the bomb or assembly). Among the strikers, the numbers vary according to sources. Painter says 50 or 60 were wounded while James Green has the number around 50 but he notes "the deaths of three civilians were recorded by the coroner, though more may have died [or been wounded] in the hail of police gunfire without having their deaths and burials recorded by the city". Given the mass arrests over the following weeks by the police, it's fairly understandable that the wounded and families of the dead would keep quiet to avoid jail.

The wrath of the police and city leaders descended on organized labor, for weeks and Chicago experienced a full blown red scare. Clergymen condemned the anarchists as agents of the devil working against God's ordained social order (the rich on top and poor below them). Newspapers were flooded with commentaries proclaiming the anarchists and other radicals vermin, dogs, "slavic wolves", and a myriad of other animal comparisons and ethnic slurs. They warned of an anarchist plot to lead the United States to insurrection. Anarchists, communists, socialists, radicals of all sorts were suspects. Hundreds were arrested and questioned (1886 questioned, not Law and Order questioned, so picture beatings) in connection with the bombing and the conspiracy to attack the police. On May 27, police indicted 8 anarchist leaders- August Spies, Albert Parsons, Adolph Fischer, George Engel, Louis Lingg, Samuel Fielden, Oscar Neebe, and Michael Schwab- for conspiracy to commit murder. Of the 8 accused, only Spies and Fielden were at Haymarket Square, but Illinois law said that anyone inciting murder is guilty of that murder. The pamphlets the IWPA had distributed calling its members to arms were used in the trial as evidence of inciting violence which lead to murder. Witnesses at the trial overwhelmingly said the crowd had been peacefully assembled and none of the speakers had called for violence or retaliation. The mayor of Chicago, Carter Harrison, had attended the meetings himself with the intention of dispersing them if they became violent, testified that the crowd was peacefully assembled and the speakers were not inciting violence. Police, on the other hand, testified that Fielden had fired a weapon at them just before the bomb exploded and that members of the crowd were armed. The men and their actions weren't on trial so much as their anarchist beliefs and their desire to change the social order (side note: none of the jurists were wage workers). 7 of the 8 men were convicted of conspiracy to commit murder and sentenced to hang. They appealed to the Illinois Supreme Court and the Court denied to hear their case. A year later, in November 1887, Spies, Parsons, Fischer, and Engel were hanged. Lingg committed suicide in his prison cell, and Neebe, Schwab, and Fielden remained in jail. Labor didn't take their execution laying down. 60,000 people petitioned the new governor of Illinois, John Altgeld, to review the case. Altgeld did indeed investigate the fact, denounced the entire trial as sham, and pardoned the remaining 3 prisoners.

(1/2) I will post the remaining bit and my sources tomorrow. It's late and my toddler doesn't care about my Redditing