Actors performed plays as a form of worship to the god Dionysus. Early in Greek theater only one actor would perform with a chorus which sang a dialogue. Later, three actors would perform in plays. The actors took on multiple roles using masks so the audience could tell the characters apart. Actors were always males, although they did play female parts.
The most famous plays were held during the Dionysia Festival in spring. A competition between various plays was held, with the winner getting a prize. Over 14,000 spectators came to watch the plays. Women were not supposed to attend the plays, but it seems they were in attendance at least some of the time.