I've discovered that the game turns your threat to 100% after 1880 B.C. And the army that attacks you on 1877 B.C. will instantly wipe your civilization out meaning you cannot progress past 1876 B.C. no matter what you do. I get it's an old game but It just seems like a design flaw and I'm completely lost as to why they decided to make that a feature.
 "Pre-Civilization Bronze Age"){kind=icon}