Eli5: Historically, time during the night was measured by ‘watches’; eg. First watch, Second watch, etc. How did people determine when one watch ended and the next began?

Question

It can’t be influenced by the moon or stars in the sky, because how would they measure the time during a moonless cloudy night?

Edit: How would, say, 3 common travellers camping on the road measure time at night?

In: 38

Answer 1

In addition to other answers, note that even modern people can still estimate time pretty well without any instruments at all. I.e., once you have a good sense of how long an hour is, whether from sundials or hourglasses or mechanical clocks or what have you, you can estimate pretty accurately what time it is and how much time has passed. Not down to the minute, but good enough for, like, waking up the next night watchman.