Greeks were the earliest recorded practitioners of stagecraft. “Skene” is Greek, translating roughly into “scene” or “scenery”, and refers to a large scenic house, about one story tall, with three doors. On the audience-side of the Skene, what are now known as “flats” could be hung. Flats developed to two-sided painted flats which would be mounted, centered, on a rotating pin, with rope running around each consecutive pin, so the flats could be turned for a scene-change. The double-sided-flat eventually evolved into the periaktos (pl. periaktoi).
As well as flats, the Greeks also used such machines as the ekkyklema, essentially a platform on wheels, and the deus ex machina, a hand-cranked lift to be used to lift a character/scenery over the skene. Over 20 such scenic inventions can be traced back to the Greeks. No light but that of the sun was used; plays started at sun-rise and continued until sun-down.
Plays of Medieval times were held in different places such as the streets of towns and cities, performed by traveling, secular troupes. Some were also held in monasteries, performed by church-controlled groups, often portraying religious scenes.
Source: Stagecraft – Wikipedia