Since he became regular writer, Grant Morrison has taken an approach 180 degrees opposite to previous famous writers. Where O'Neil and Adams and later Miller mostly ignored most of the past stories, especially those done in the 50s, Morrison has excavated many discarded concepts that had been as out of continuity.
He mentioned his first idea was to have a Batman replacement groomed by the police but it turned out this had already been done in the 50s. He came to realize that every kind of story had already been done in the long published history of the character.
I'd like to make a long list of all the concepts that Morrison excavated.
But here I'll focus on just one. Batman and Robin #16 announced the next phase as Batman will now recruit and train international Batmen. That isn't a new idea. It's the same idea as the Club of Heroes or International Batmen that had been done in the 50s.
First, in Batman #56, Batman trained Bat-Hombre but he turned out to be a member of an outlaw band. In Batman #62, he met the Knight and the Squire in England. In Batman #65, he trained Wingman. In Batman #86, he met the Sioux Man-of-Bats and his son Little Raven. Detective Comics #215 Batman invites the Knight and Squire, the Musketeer, the Gaucho, the Ranger and the Legionary. In World's Finest Comics #89, philanthropist John Mayhew invites Batman and Robin, Superman, the Legionary, the Musketeer, the Gaucho, and the Knight and the Squire to award them membership in his Club of Heroes.
The characters were then forgotten except by Roy Thomas who kept their adventures in the 50s and tied them to the JSA rather than to Batman.
Under Morrison, The Knight and Squire joined the Ultramarine Corps in JLA #26 and had an adventure with them in JLA Classified #1-3.