| This article is about the technology in Age of Empires II. For the technology in Age of Mythology, see Boiling Oil (Age of Mythology). |
Boiling Oil is a technology in Age of Empires II: The Forgotten that is unique to the Persians and can be researched at the Castle. Once researched, it gives Castles +9 attack against rams (effectively resulting in 6-8 additional damage, depending on the type of ram). It only affects the first arrow; all additional ones only do the minimum damage of 1.
In the Definitive Edition, this technology was replaced by Kamandaran, which changes the gold cost of the Archer line to wood.
Strategy 
Edit
As buildings, Castles are weak against siege units like rams, which have an immense attack bonus against buildings. Boiling Oil enables Persian Castles to defend slightly better against them, though any more than one Ram still requires the attention of melee units. Bombard Cannons and Trebuchets of course still outrange Castles and remain a heavy threat, but unpacked Trebuchets do get the bonus damage from Boiling Oil. University upgrades should be researched to increase the efficiency, especially Murder Holes since without it, as soon as the rams get beneath the Castle, Boiling Oil becomes useless. Blacksmith upgrades also add range to the Castle and should be researched, as they increase the time to apply the extra damage.
Team bonuses Edit
Changelog Edit
Definitive Edition Edit
- Boiling Oil replaced by Kamandaran.
Trivia Edit
It cannot be said that the employ of boiling oil in siege warfare was invented by the Persians, or that it was even especially adopted by them. Its first recorded use was 67 AD in Yodfat (or Jotapata, located in northern Israel) against Vespasian's legions. Beyond that, the lack of evidence shows that the use of boiling oil for defense was rarely seen throught History .
| Unique technologies | |
 The Conquerors | |
|---|---|
| Garland Wars | Yeomen | Logistica | Furor Celtica | Rocketry | Bearded Axe | Anarchy | Perfusion | Atheism | Kataparuto | Shinkichon | El Dorado | Drill | Mahouts | Zealotry | Supremacy | Crenellations | Artillery | Berserkergang | |
 The Forgotten | |
| Atlatl | Warwolf | Greek Fire | Stronghold | Great Wall | Chivalry | Marauders | Andean Sling | Couriers | Sultans | Shatagni | Pavise | Silk Road | Yasama | Panokseon | Corvinian Army | Recurve Bow | Obsidian Arrows | Nomads | Boiling Oil | Madrasah | Orthodoxy | Druzhina | Inquisition | Ironclad | Sipahi | Chieftains | |
 The African Kingdoms | |
| Kasbah | Maghrabi Camels | Tigui | Farimba | Royal Heirs | Torsion Engines | Carrack | Arquebus | |
 Rise of the Rajas | |
| Howdah | Manipur Cavalry | Tusk Swords | Double Crossbow | Thalassocracy | Forced Levy | Chatras | Paper Money | |
 The Last Khans | |
| Stirrups | Bagains | Steppe Husbandry | Cuman Mercenaries | Hill Forts | Tower Shields | Silk Armor | Timurid Siegecraft | Kamandaran | |
