Brief history of theatrical tradition in Italy (and a bit of Europe)

• Classical theater, Greece and Rome. Performances in open space (arena). Look up Epidaurus https://youtu.be/2CVO9Vd067U ;  Pompeii https://youtu.be/f5xVOyX7n-s  
   

• The Sacred Drama: late Middle Ages, representation of the last days of Jesus, last supper, betrayal, arrest, torture, trial and crucifiction.
   

• Middle Ages to Renaissance: street performers, nomadic groups, no structure to the plays, mostly comical and for the low classes. See the Three Stooges (2 minutes will be enough to give you the idea https://youtu.be/C1YXMYjPYfc  )
   

• These two traditions converge into theater for the aristocracy, with improvisation based on a basic storyline. COMMEDIA DELL'ARTE.  KABUKI THEATER https://youtu.be/67-bgSFJiKc
  NOH THEATER https://youtu.be/108d4KnZPxo   BEIJING OPERA https://youtu.be/vtV3iAuYN48
   

• The first indoor theater in the west was in the town of SABBIONETA, built by the Gonzaga, lords of Mantua as some kind of ideal classical city (also known as The Little Athens.)
  Theater   https://youtu.be/IFc4W1u7Zzg  The Ideal City https://youtu.be/qvBGz5h_hug
   

• GOLDONI: theater for the rich Venetians, about their vices, foibles, neuroses. It's the modern theater, like the stuff you can see on Broadway today. It deals with daily issues, in dramatic terms of course. Films are based on the same principles and structural underpinnings.
  
  ONE MORE THING: modern music notation Guido d'Arezzo https://youtu.be/l-JMX7tVqog