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general::
Also, old war horse. A dependable, frequently performed attraction, as in The opera company is doing nothing but old war horses this season, like Aïda and La Bohème. This term originated in the mid1600s for a military charger that had been through many battles. In the 1800s it began to be used for human veterans, and in the mid-1900s for popular productions, especially of musical works.
American Heritage Idioms