Mary-Louise Parker was on the point of being signed for the part of Kitty when director Neil Jordan got a call from Julia Roberts expressing interest in the role.
John Boorman's short segment from Lumière and Company (1995) was filmed on the set of this movie (most precisely the location used for the Easter Rising sequence) and features actors Liam Neeson, Aidan Quinn, Stephen Rea and Alan Rickman.
Thomas MacDonagh surrendered at Jacob's Factory; he wasn't present with GPO leaders Pearse, Clarke or Connolly when they surrendered at 16 Moore Street.
There is a speech de Valera makes to a crowd after the treaty with England is signed. He states in his fiery speech that "only pure blood Irish" should be able to participate in the new Republic, but he would have not said this since his father and surname were Spanish, a fact which his political opponents would use against him.