I went to the nutcracker ballet tonight and was left thinking that surely these types of productions occurred prior to electric lighting, and it seems insane to me that these types of productions were lit with candle light. Am I just confused on my time periods or did they have some tricks/techniques to make this happen, even just dimming the house lights seems like a monumental undertaking if you were relying on candle light.
The same way all other lighting worked before electricity - candles, whale oil, kerosene, and gas lamps. There were typically footlights installed every two or three feet across the front of the stage floor. Over-stage chandeliers were used for overhead lighting, especially of the fore-stage.
See: A Brief History of Stage Lighting and The Stage Lighting Museum.