Egypt-> Mongolia is a conquest eitherThe problem is that you have civilizations that transform randomly like Egypt (agrarian and sedentary African civilization) into Mongolia (a nomadic and livestock-based Asian civilization) just because Egypt has 3 horses and they will necessarily have different characteristics, how do we justify the transformation of a civilization (Egypt) that expanded little and lasted thousands of years (which therefore should have growth and culture as its main characteristics) into one that founded a huge empire and which however was divided into various states in a few centuries and then disappear quite quickly (which therefore should be based on militarism and expansionism)?
I have Humankind and unfortunately the civilization change part of the game is considered the WORST part because in everyone's opinion, it makes the game not a campaign, but a series of scenarios without any connection
external (plains nomads invaded for your bountiful horses)
OR
internal (some of the locals in the cities you founded had a strong horse traditions. over the past few centuries they have spread in power, eventually Imperial troubles allowed ambitious Cavalry generals to get more control…to the point where warlordism became a way of life)