A great historical game doesn't have to be ruined by history. Relic Entertainment knew from the beginning that Age of Empires 4 would feature The Mongols. They were both the lynchpin civilisation and an iconic force of Age of Empires 2. Their lightning-fast horse cavalry was a highlight of their empire that spanned nine million miles. This included almost all of Relics' game world.
Quinn Duffy, games director, said that we were like, "Okay, well they fought everyone." Now we can begin to determine who else we can include."
Now, the task was to convert 500 years of history into the essence of a civilisation. This abstraction was concocted to match the rules of a game.
Some historical elements were perfectly mapped. Odegai Khan, third son of Ghengis expanded a giant Yam network. This was an early pony express. These were postal stations that allowed horses or runners to rest while they sent messages across the empire. Relic's team reimagined them into small stone circles, outposts that offer units speed bonuses as they ping around players bases.
Other ideas were dropped. The team motion-captured horses. The new game would have horses that move in a realistic way. Instead of being cartoonish, the animations will show them slowing down and moving in circles towards their target. It was impossible to play. It was hated by everyone, Adam Isgreen, the franchise creative director at Worlds Edge who collaborated with Relic to create the game.
Finally, there are aspects that Duffy and Isgreen both acknowledge as simply historical. Age of Empires 4's Mongols are nomadic. Their towns can be moved around the map by moving them on wagons. Duffy says that this may seem authentic but it is not true. The Mongols started to settle in the Ghengis Khan era, and they were eventually absorbed by his grandsons and great-grandsons. He says that it is always a challenging battle. We are always battling with authenticity and how to translate that authenticity into gameplay.