This year marked the 75th anniversary of the Batman.
There have been many incarnations, the campy 60s version, the animated version, the version with the nipples. Every version of Batman begins the same way, with young Bruce Wayne witnessing his parents gunned down after a night at the theater. And what they saw that night has remained pretty consistent over the last 75 years : The Mark of Zorro.
There have been a few variations along the way, sometimes its the Tyrone Power version, sometimes its the Douglas Fairbanks version from the 1920's, recently in the Nolan Universe it was actually a performance of Mephistopheles. But for the most part the established story is that the Waynes watched some version of The Mark of Zorro that night.