Divaythsarmour
Adventurer
Army composition is Chariots/Horse Archers, and Bowmen and in a reverse of positioning horse archers and chariots are used as city defenders until more Formation and the much neglected Cover promoted Bowmen are available.
I've had considerable success using large numbers of chariots & horse archers to defend cities, especially when attacked by huge stacks with catapults.
The trick is not to just sit behind the walls and wait for them to attack, but to attack them first when they pull up next to the city. With a barracks and stable in the cities where you're building, they'll have the maximum promotions right from the start. The large numbers and the two promotions will help a good number of them survive, even when the attacking stacks have spearmen. The survivors will be promoted again and more likely to survive again. Later, they can be upgraded to knights, cavalry etc. This can be an excellent technique with Cyrus and the Great Wall.
I had one game where Tokugawa was attacking relentlessly with massive stacks. I must have popped 4 GG's during the horse archer era alone. I like to put all those GG's in the best production city to pump out highly promoted units. Eventually you get an army that's so highly promoted, that the other civs (even if they're more technically advanced) can be crushed by the strength of the promoted units.