There were several big theatres (warning this link contains an image over 114kB in size) in Rome for the performance of plays. The plays there were not plays as we know them today. Theatre was very important in the lives of the Romans. Theatre was another way of keeping people busy, and happy so they would not plot against the emperor. Ideas were copied from the Greeks. The problems of sound and light, which the Greeks had solved by performing outdoors, and building a place with semi-circular tiered seating today in Rome - the theatre of Marcellus.
The huge amount of people present still held problems for the sound as the audience would not always stay quiet.To solve this problem, costumes and mask were worn to show the type of person on stage. Different symbols were worked out. The actors wore masks - brown for men, white for women, smiling or sad depending on the type of play. The costumes showed the audience who the person was - a purple gown for a rich man, a striped toga for a boy, a short cloak for a soldier, a red toga for a poor man, a short tunic for a slave etc. Women were not allowed act, so their parts were normaly played by a man or young boys wearing a white mask.
The actors spoke the lines, but a second actor mimed the gestures to fit the lines, along with backround music. Some things are represented by a series of gestures, which are recognised by the audience to mean something, such as feeling a pulse to show a sick person, making the shape of a lyre with fingers to show music.
Some of the plays performed in the theatre were as disgusting as some of the gladiatorial fights. For instance, in a play showing the story of Daedaus and Icarus, an actor actually tried to fly, and fell to the ground and was killed. The play was a big success because of it.
Emperors such as Nero used the theatre as a way of showing their own talents - good or otherwise. Nero actually used to sing and would not let anyone leave until he was finished.