But candles don't seem to have been around that long. Reliable sources are hard to find online (one page talks about the ancient Romans of 3000 BC...) but Wikipedia says dipped candles go back 2500 years to the Romans, or 2200 years to the Chinese. (This is distinct from rushlights, soaking a reed in tallow and burning that.)
What I don't usually imagine is oil lamps:
But they seem to have been around from 15,000 years ago, or earlier, and used up into 1800s America, across many cultures, including Inuit seal blubber lamps. Similar materials as candles, with less labor. Similar shapes across time and culture, a shallow dish with a place for a wick, apparently for physical reasons: vegetable oils and melted animal fats are 'heavy' and don't go far up a wick via capillary action, so the burning wick has to be close to the oil. (The same is true of candles, but there the wick follows a shrinking column of wax, whether by self-burning or by human trimming.) With more lightweight spirits (distilled alcohol) or lighter kerosene/paraffin oils, you can have a wick in a tall jar of fuel and have it work.
This is why Aladdin's lamp is a lamp, despite looking maybe like a squashed teapot: it's an oil lamp, and the spout is for the wick, not for pouring something out.
Handmade lamps using clay are like 6500 years old, but shells and stone bowls were used before that. The cave paintings were painted by the light of animal fat in stone depressions.
This monograph describes someone buying and using several different oil lamps, including trying solid fuels, and the late Crusie and Bette/Betty lamps of the 1700s and colonial America.
So when you're thinking about fantasy/pre-industrial settings, and how they see in the dark... don't just imagine candles and large fires, but oil lamps! (But not the late Argand lamp, reworking how burning vegetable oil could work, or the more modern kerosene oil lamps, both of which look very different.)
The UU flaming chalice doesn't seem to directly be an oil lamp.
See the DW comments at https://mindstalk.dreamwidth.org/534729.html#comments