Castle (Age of Empires II)

The Castle is a military building in Age of Empires II available once the Castle Age is reached. It is a powerful fortification with many different functions and can accomplish the following:

Being the building with the most uses and functions, the Castle is one of the most powerful buildings in the game but requires huge amounts of stone. The best counter for Castles are siege weapons, such as rams, Trebuchets, Bombard Cannons, or Petards. The AI usually builds a relatively high number of Castles close to the center of the map starting from the Imperial Age in Deathmatches.
 * Can heal and garrison up to 20 units simultaneously.
 * Train the unique unit of a civilization.
 * Allows the player to develop the unique technologies of a civilization and can promote unique units to elite levels once Imperial Age is reached.
 * Allows the player to construct Trebuchets and Petards.
 * Can support up to 20 population.
 * Allows the player to gain control over a foreign territory.
 * Can fire five arrows within its range without garrison, while a fully garrisoned castle can fire up to twenty one arrows simultaneously.
 * Allows for advance to Imperial Age without having to build two Castle Age technology buildings.

When playing Regicide each player starts with an additional Castle near to their Town Center.

History
''The first castles appeared in Europe in the ninth century as an improvement of the local lord's stronghold. Castles were tactically defensive but strategically offensive. Because they were so difficult to capture if adequately defended, they provided a secure base from which a mobile force of warriors could extend political control. A local lord installed himself inside with a professional force of fighing men to serve him. Castles spread across Europe in the tenth and eleventh centuries in response to weak central authority and barbarian raids from the north and east. Kings spent the rest of the Middle Ages trying to take back control of castles raised by local lords. The development of dependable mobile heavy artillery in the fifteenth century finally made castles obsolete.''

Tactics and Placement
Players should build Castle inside minor fortifications outside their settlement. Surrounding the entire base with walls along with other towers such as a Bombard Tower provides additional protection from Battering Rams and other melee units. If a river separates their base from the enemy's, players should wall up the river's shallows and build a Castle near them. Players should build Castles at major chokepoints, especially if they have researched the Murder Holes upgrade. Players should also garrison a few cavalry units to fend off Battering Ram attacks.

Alternatively, players may build Castles inside their bases, which protects the economy against enemy raiding effectively, while making the Castles less vulnerable against long ranged siege units like Trebuchets.

For Teuton players, researching Crenellations adds to castles +3 range and this allows for them to match the range of regular Bombard Cannons and regular Cannon Galleons. However players must keep in mind to avoid a siege with those kind of units at any cost if they want to keep their Castles safe, Trebuchets are a heavy threat to the Castles.

If running for a Relic or Wonder victory, Castles can become very useful to build up the defense of the Wonder or the Monasteries holding Relics, but the support of other structures such as walls and towers is required. Also, the player must have sufficient numbers of troops (specially cavalry) for countering the opponent siege units. In Regicide games, the Castles is in most cases a safe place for the King if properly supported by other defensive structures.

Attack/Range damage
An empty Castle is able to fire five arrows at a time, with a base damage of 11 each. Garrisoning either villagers or non-siege ranged military units (archers, cavalry archers, hand cannoners, skirmishers), would add additional arrows for the Castle. Up to maximum of 21 arrows, 1 base arrow and 20 additional arrows; the castle inherently already has 4 "power" which is listed in the attack with parenthesis. Not all garrisoning units are the same for the purposes of additional arrows provided to the castle, their value is generally dependent on two factors: attack speed and total damage. The more powerful and faster a ranged unit can attack, the better.

For a Teuton player researched Crenellations, fully garrisoning infantry of the same type would enable the castle to fire 12 arrows (7 extra).

The following table shows the maximum number of arrows a Castle can fire, when it is garrisoned with units of the same type:

Civilization Bonuses

 * Chinese: The cost of technologies that benefits Castles and Castle technologies is 10%/15%/20% lower in Feudal/Castle/Imperial Age.
 * Aztecs: Castle units are produced +15% faster.
 * Spanish: Castles are built 30% faster.
 * Byzantine: Castles have 10%/20%/30%/40% more hp in Dark/Feudal/Castle/Imperial Age. Town Watch (+4 LOS for buildings) is free.
 * Teutons: Teutons get Murder Holes for free upon reaching the Castle Age.
 * Franks: Castles are 25% cheaper.
 * Incas: 15% stone discount on buildings applies to the Castle.

The Forgotten Changes

 * Castles +1 Line of Sight (due to a bug)
 * Koreans Can build Castles and other fortification structures 25% faster.

Units and Technologies
Castle Age
 * 1 Unique Unit (see List of unique units in Age of Empires II)
 * Petard
 * Castle Age unique technology (see Unique Technology, in The Conquerors only Goths have two unique technologies, in The Forgotten every single civilization has two)

Imperial Age
 * Elite version of the unique unit
 * Trebuchet
 * Imperial Age unique technology (see Unique Technology)
 * Hoardings - Castles +21% HP
 * Sappers - Villagers +15 attack against buildings
 * Conscription - Barracks, Archery Range, Stable and Castle units train 33% faster
 * Spies / Treason - For Spies: Can see enemy's Line of Sight, For Treason (only in Regicide game mode): See enemy Kings for a short time.

Architecture
Each architectural group of civilizations has its own unique designs for its Castle:
 * West European (top left) has one tower and a drawbridge.
 * Asian (bottom, second from left) bear an uncanny resemblance to the main keep of Japan's Osaka Castle.
 * Middle-Eastern (top, second from left) Islamic architecture with gold-brown colors (perhaps made of sandstone).
 * Central European (bottom left) has a blocky design with four tall towers and two shorter ones with a bridge in between, bearing a distinct (and ironic) resemblance to Rochester Castle in England.
 * Meso-American (top, second from right) resemble tall stepped pyramids, with a steep staircase leading to the top.
 * Italians and Portuguese have a Castle for their own architecture (bottom, second from right), with a Mediterranean style. Their Castle appears to be based on the Castello di Torrechiara in Parma, Italy.
 * East European Castles (top right), resemble the Malbork Castle in Poland.
 * Mali and Ethiopian Castle (bottom right).

Trivia

 * The entrances of the West European, Italian, East European and the Meso-American Castles head to the left, the entrances of the three others to the right.
 * The castle is the most expensive building in the military sector.