On her blog Living the History, Elizabeth Chadwick looks at lighting in the Middle Ages, from firelight to candles to lanterns. The article includes illustrations and sources.
Elizabeth Chadwick concludes:
It wasn’t a world without light, but it was certainly one more deeply shadowed, more golden, more smokily scented (among other smells!) than ours. It couldn’t be had for the flick of a switch, but provision of light had to be thought about and toiled over. What you never have, you never miss, but a thousand years ago, the return of daylight as the Northern hemisphere turned towards Spring, must have come as a truly keen pleasure of life.