By the time the crowd filled Jaleh Square in Tehran on 8 September 1978, the air of protest in Pahlavi Iran had already been building for months. People had gathered against Shah Mohammad Reza Pahlavi, unaware that martial law had been declared the day before. Then the Imperial Army of Iran ordered them to leave and opened fire, and the square became the place later known as Black Friday.

The facts of that morning are stark. In the main account, 64 civilians were killed and 205 injured in Jaleh Square, with Spencer C. Tucker also recording 30 government security forces dead. The Iranian government gave a far lower figure, while opposition voices and Western media spoke of thousands. Andrew Whitley of the BBC reported that hundreds had died, and Michel Foucault first wrote of 2,000 to 3,000, then 4,000. The confusion itself became part of the event.

Black Friday did not come out of nowhere. During the first half of 1978, protests against the Shah’s rule spread, and the government answered with martial law. On 8 September, thousands gathered in the square in Tehran, and the army’s gunfire turned a political challenge into a national shock. Historian Ervand Abrahamian later called it a sea of blood between the shah and the people, and that is not exaggeration in tone, but in consequence.

The massacre ended any hope for compromise. Abbas Amanat notes that clerical activists, backed by the Qom marja's, seized on the killings to portray the regime as brutal and illegitimate, while rumours multiplied in the absence of reliable reporting. The opposition said thousands had been massacred by Zionist troops, and the numbers swelled far beyond the later tabulations. What mattered was the political effect: the protest movement hardened and the regime lost trust.

The following months carried the country towards collapse. Protests continued for another four months, and on the day after Black Friday Amir-Abbas Hoveyda resigned as minister of court for unrelated reasons. In October, a general strike shut down the petroleum industry, sealing the Shah’s fate. By January 1979, Mohammad Reza Pahlavi had left Iran, and Ayatollah Ruhollah Khomeini led the revolution that ended the monarchy less than five months after the shootings.

After the revolution, Jaleh Square was renamed the Square of Martyrs, Maidan-e Shohada. The memory also moved into art: in 1978, Hossein Alizadeh set Siavash Kasraie’s poem about the event to music, and Mohammad Reza Shajarian sang Jāleh Khun Shod, meaning Jaleh turned to blood. Later, Nastaran Akhavan wrote Spared about surviving that day, and the 2016 game 1979 Revolution: Black Friday returned to the same square and its 8 September 1978 dead.