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This article is about the technology in Age of Empires II. For other uses, see Boiling Oil.

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 is replaced by Kamandaran, which changes the gold cost of the Archer line to wood.


As buildings, Castles are weak against siege units like rams, which have an immense attack bonus against them. 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.


Definitive Edition[]

  • Boiling Oil is removed from the game.


  • Before its removal and replacement in the Definitive Edition, Boiling Oil was considered one of the weakest unique technologies (along with Atheism), and almost never saw any use in multiplayer matches, and with no known instances of being researched in the competitive scene.
  • 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 through history; in the Middle Ages, use of boiling water and hot sand were considerably more common defense techniques.[1]