Siege weapons (Age of Empires II)

Siege Weapons in Age of Empires II become available in the Castle Age. They are powerful machines that excel at taking town enemy buildings or at battle against massed units. Unit upgrades for siege weapons as well as long-range siege weapons are only available in the Imperial Age.

They are built at the Siege Workshop or Castle. With the exception of Rams, Siege Towers, and Petards, all siege weapons possess a mid-to-long range.

General Information
Like ships, siege weapons cannot be healed by Monks, but have to be repaired by Villagers instead. Repairing siege weapons costs gold.

All siege weapons cost wood and gold, with the lone exception of the Petard, who costs food and gold. Generally speaking, siege units are the most expensive units and take longest to train.

In order to train Bombard Cannons, Chemistry must first be researched.

Siege weapons and Monks are the only units than can initially not be converted. In order to convert siege weapons, Redemption must be researched.

Trebuchets, Onagers (since The Forgotten), and Siege Onagers can kill trees, making them the only units being able to do so, next to, of course, Villagers. That can be of high strategic importance, especially in maps with dense forests, e. g. Black Forest.

All information that follows is current as of patch 5.0.

Categorization
Siege weapons are best divided into two categories: units that main purpose is to destroy buildings and units that excel at combat against enemy infantry and archers.

Anti-building
 * Rams
 * Bombard Cannons
 * Petards
 * Trebuchets

Anti-unit
 * Mangonels
 * Scorpions
 * Bombard Cannons
 * Organ Guns

Since The African Kingdoms, the Siege Tower cannot attack enemy structures or units and cannot be put in any of the categories above. In The Forgotten, it was able to attack, but its main purpose was still the transport of troops. So even there it does not fit in any of the two categories.

The Bombard Cannon can be put in both categories since it can outrange almost all buildings, but also can be effectively used against enemy units.

Although the two types of units can still fulfill each other’s roles, they are generally ineffective at doing so. For example, while Mangonels are devastating against groups of infantry and can outrange Town Centers, they deal little damage to Castles. Trebuchets, on the other hand, are excellent against fortifications but almost never hit any unit they target - excluding, to some extent, other Trebuchets.

List of Siege Weapons
Marked with yellow background are unique units.

Technologies
Listed below are all technologies that benefit siege weapons. Marked with yellow background are unique technologies. This list does not contain unit upgrades.

Civilizations
The Slavs, Celts, and Ethiopians have the best siege weapons due to their civilizations bonuses and unique technologies.

The Ethiopians are the only civilization to have access to all units from the Siege Workshop.

Civilization Bonuses
The following civilizations have bonuses that specifically benefit siege weapons:
 * Celts: Siege weapons fire 20% faster.
 * Chinese: Demolition Ships have +50% HP.
 * Huns: Trebuchets are 30% more accurate.
 * Slavs: Siege Workshop units are 15% cheaper.
 * Spanish: Cannon Galleons benefit from Ballistics.

Team Bonuses
The following civilizations have bonuses that specifically benefit siege weapons:
 * Celts: Siege Workshops work 20% faster.
 * Khmer: Scorpions have +1 range.
 * Koreans: Mangonel minimum range reduced from 3 to 1.