That afternoon, a combined police and military force, with orders to carry out a search operation, descended on Croke Park, where a Gaelic football game between Tipperary and Dublin was taking place.
What unfolded there was a massacre that changed Irish history.
The events of that infamous day almost 100 years ago are remembered in the documentary Bloody Sunday, 1920 on RTÉ1 on Monday, November 16 at 9.35pm.
On November 21, 1920, in Croke Park, 90 seconds of shooting claimed 14 lives, and left around 60 people wounded, both players and spectators.
The youngest victim was 11-year-old William Robinson of Dublin, while among the dead were Jane Boyle, who had gone to the match with her fiancé and was due to be married five days later.
Tipperary footballer Michael Hogan was killed and a stand at the ground was named in his honour.
For nearly a century, the full story of what happened on Bloody Sunday was locked away; the story of the Croke Park victims was lost.
This documentary, based on the award-winning book, The Bloodied Field, by Michael Foley, lifts the veil on the events of that day, recounting one of the darkest days of the Irish War of Independence from the perspective of those who participated and perished in its horror.
Featuring contributions from family members of those who died on the field, as well as leading historians and academics, the programme recounts the dramatic events of a vicious day, and places them within a wider context of national identity and cultural history.
It also explores our relationship to myth, collective memory and commemoration.
Broadcast on the week when the centenary of Bloody Sunday will be marked at Croke Park and elsewhere, the documentary brings to life one fateful day during a complex tit-for-tat war in which spies, informers and agents were commonplace.
The programme was directed and produced by IFTA-nominated filmmakers, Keith Walsh and Jill Beardsworth of Twopair Films.