Original: Until the Hellenistic period , all tragedies were unique pieces written in honor of Dionysus and played only once , so that today we primarily have the pieces that were still remembered well enough to have been repeated when the repetition of old tragedies became fashionable ( the accidents of survival , as well as the subjective tastes of the Hellenistic librarians later in Greek history , also played a role in what survived from this period ) .
Simplified: Until the Hellenistic period , all tragedies were unique pieces written in honor of Dionysus and played only once , so that today we only have the pieces that were still remembered well enough to have been repeated when repetition of old tragedies became fashion .