Historically, HOW Empires & Dynasties have Collapsed:

WHEN EMPIRES COLLAPSE (2 at the least, 4 at the most, occurs simultaneously):
(a) Disease Pandemic, Disease Outbreak
(b) War, Revolution, Rebellion, Independence Movements Emerge, Suppression
(c) Economic Collapse
(d) "Climate Change" and Natural Disasters (ex: drought, famine)



WHY?
Because trade routes are disrupted, business is halted, food becomes scarce, mass emigration occurs, money becomes worthless, jobs are scarce and hard to find.



RESULT:
New identities are formed, New lifestyles are created, New myths and narratives are created, New Gods and belief systems/ideologies are implemented, New forms of governments and New rulers take over, and the "old world" becomes nothing more than a faded memory, which some of the living will romanticize and others will want to forget in order to rebuild their lives and move on.