Haymarket affair — aftermath of a bombing that took place at a labor demonstration on Tuesday, May 4, 1886, at Haymarket Square in Chicago
The 1886 Haymarket bombing and trial shaped international labor movement history and is recognized as the origin of International Workers' Day.
Key Facts
- Date of bombing
- May 4, 1886
- Police deaths
- 7 officers
- Civilian deaths
- at least 4 civilians
- Anarchists charged
- 8 people
- Executions carried out
- 4 hanged on November 11, 1887
- Pardons issued
- 1893, by Governor John Peter Altgeld
By the Numbers
Location
Cause → Event → Consequence
Workers across Chicago were striking for an eight-hour workday in May 1886. On May 3, police intervened at a McCormick Harvesting Machine Company rally, killing two demonstrators and injuring many others, prompting labor organizers to call a follow-up demonstration at Haymarket Square the next day.
On May 4, 1886, as police moved to disperse the Haymarket Square rally, an unknown individual threw a dynamite bomb into their ranks. The blast and subsequent retaliatory gunfire killed seven police officers and at least four civilians, wounding dozens more. Eight anarchists were tried for conspiracy; four were ultimately hanged after a widely criticized legal proceeding.
The trial and executions drew international attention and condemnation. Illinois Governor Altgeld pardoned the surviving defendants in 1893, denouncing the trial as unjust. The event became a touchstone for the global labor movement and is broadly recognized as the origin of International Workers' Day, observed on May 1 worldwide.
Belligerents & Mobilization Analysis
Side A
1 belligerent
Side B
1 belligerent