I once read that this was based on a true event (SPOILER WARNING)

(SPOILER WANING)

It has been years ago and I don't remember where I read about it and maybe someone can help and share their thoughts and maybe provide links about the real events.

In real life the events fairly followed the movie. The Aldo Ray character led the robbers in 1906 for the Irish patriots and they were to split the money but when an agreement was reached and the robbery canceled by the Irish Ray and 2 of the other robbers tried to finish the robbery on their own but were caught by the alertness of a guard played by Peter O'Toole. Each of the robbers were sentenced to 20 years in prison but Ray's character and one of the others were pardoned early with the agreement they would serve in the English military during the World War 1 years. The third robber had already died in prison. The other robber was killed in action during the war but Ray's character survived and he married one of the Irish ladies (played by Elizabeth Sellars)who was part of the Irish robbery conspiracy. Also after the war Ray's character obtained employment with a manufacturing company where he worked until he passed away in 1938.