You take the role of one of 5 different nobles (Albion, Valios, Anjou, Aragon, and Burgundy), fighting for the title of King of Britagne. In addition, 3 territories are controlled by the Pope. Depending on which noble you pick you can start at any of 5 general areas of the map. You begin with one territory of a specific type: Gold, Timber, Iron, or Food. Having more of one kind of resource territory increases the total amount you can harvest per turn (also dependent on the total amount of "points" allocated).
At first you can perform one task each of three types at once: green (resources and castles), red (army and policing), and blue (scouting, diplomacy). The more you use, the more points you gain (to a limit of 8 per type), and the ability to perform two tasks of each type (green first, then red, then blue).
Gameplay is straightforward: scout out unknown territories, conquer them, build castles to prevent revolts and line your defenses, raise an army, feed and pay them, and eventually make a claim for the title. Be careful; the other 4 nobles are working just as fast as you and will eventually make the claim themselves. Depending on how strong you or they are, the Pope will decide whether or not to endorse the claim. Therefore, attacking someone that claims the title can prevent them from getting it. Using diplomacy also allows you to maintain high relationships with the other nobles and with the Pope, a useful feature to protect yourself from attack. Once making the claim, you would lose that protection, so be sure to make it only when you're able you can defend yourself against multiple attacks.
Alternately, you can conquer everyone and even the Pope to win by default, though that is difficult to do and requires a huge army.
The most unique feature at the time for Castles II: Siege and Conquest was the ability to design and save different castles. Depending on the total number of walls, the castles were assigned point values that determined how much it cost to build and how long. Larger castles also were harder to destroy or capture, which served to keep enemies out of your lands. Large castles are also used to prevent revolts; your people will leave your leadership if there is no nearby castle worth more than 100 points after a certain amount of time.
Army management is simple: Infantry, Archers, and Knights, each using a different resource. Infantry use one Iron, Archers; one Timber. Knights use 2 Iron and 2 Timber to raise. The size of the army you can raise is dependent upon the number of territories and castles you possess. Therefore, the larger your holdings, the larger the army you can keep. Every 6 months alternating costs an equivalent amount of Food, then Gold to feed and pay them, respectively.
Having a large army will deter attacks from neighbors but will use huge amounts of resources, which can make it difficult to build enough castles and defenses (including catapults and siege towers). The trick is to balance an army and resource gathering to ensure you can feed and pay them, build your castles, and keep enough in case of sabotage or trade, while you wittle down your enemies and get ready to be the King of Britagne!

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