The player can choose to play as one of six different civilizations: There are ten scenarios, each requiring the player to reach a specified Age before being unlocked for play. The game features a PvE campaign mode, titled Historical Challenges, that puts players in a series of historically based scenarios.
Players can also form alliances with each other for various social and strategic functions, such as supplying each other with relief forces, which help players to defend against enemy attacks. Researching new technologies grants multifarious advantages to the players, such as additional crowns in case of victory, and reduced resources that can be looted from the player from each attack. Upgrading buildings is needed in order to generate resources faster, hold more resources, defend the castle against enemy attacks more efficiently, and unlock new technologies. The trained troops are used to attack other players' castles in order to loot their resources and to earn crowns, the game's scorekeeping mechanism.
In Age of Empires: Castle Siege, the player maintains and develops a castle that produces resources, which can be used to train and upgrade buildings and troops, as well as research new technologies.
