Some say the Book of Enoch was not written by Enoch around 3000 to 2500 BC but by a pretender around 300 BC. So how, if the writer of the Book of Enoch was born a few hundred years BC, would he have known that the emergence of these things happened in 3000 or thereabouts BC? Face painting, idol making, magic arts, divination, writing, weaponry such as maces, alloys using copper and antimony, warfare, worship of angels and demons and demi-gods (half human, half god - or half human, half angel), sorcery, etc. These appear in archaeology of the time. How would he know it appeared first in the Hermon area and spread out from there throughout the next few hundred years? How would he know it happened just before the time of the Flood recorded in the Sumerian King List? How would he know there were seven kings up to the time of Enoch starting with Adam (Alulim)?
