How is the need for line memorization in theater actors similar to or different from the need for line memorization in film actors?

It is more critical for theater actors to have their lines firmly memorized because their performances are going to be live.  With a TV or film actor, for the most part, they can ask for the line and retake the shot.  There are a few live television shows but for the most part, things are recorded so while it is important for film actors, it is imperative for theater actors.

The gregorian chant was a major cultural milestone in the middle ages. it was one of the first codified forms of music meant to be played as written, where previously it was difficult to mass-produce and disseminate any music. what's more, these chants were also some of the first examples of musical notation: the notes and bars of today's music sheets are a reflection of centuries of evolution beginning with these chants. it became official throughout the entirety of the catholic church, meaning that nearly all of europe followed this musical notation and styling.