Years ago at one of the SCA events I attended in the summer, we had an enormous, raging campfire every evening. By the wee hours of the morning, just when everyone was ready to turn in, the fire would be burned down to a wonderful bed of coals that would have been perfect for cooking. It was really a shame that nobody was going to cook anything at 2 o'clock in the morning.
That's why all those ancient cast-iron kettles had feet on them. You didn't hang them over a fire. You sat them on a bed of coals.