"The Unknown Warrior at Westminster Abbey, November 1920" In order to commemorate the many soldiers with no known grave, it was decided to bury an 'Unknown Warrior' with all due ceremony in Westminster Abbey on Armistice Day in 1920. A view of the coffin of the Unknown Soldier in Westminster Abbey, November 1920, showing the inscription on the beaten iron plate. The coffin is propped up to almost vertical on a stand.