I know that in ancient times puzzles and riddles were as popular—if not more popular—than they are now. (Let us define "ancient times" as any time predating the fall of the Roman Empire, around A.D. 470).
Many of these puzzles survive to this day, e.g. the Sphinx Riddle ("What animal walks on four legs in the morning, two at noon, and three in the evening?"), or variants of "measure X amount of liquid, having only vessels of Y and Z sizes".
Are there any riddles or puzzles left from these times for which the answer was either lost or never known? Can you provide any?