Celts/Tree

Tech Tree Exclusions
The Celts have access to all units, buildings, and technologies, apart from the following:

Archery Range
Units Upgrades
 * Arbalest
 * Hand Cannoneer
 * Thumb Ring
 * Parthian Tactics

Barracks
Units Upgrades
 * Eagle Warrior -> Elite Eagle Warrior
 * Squires

Stable
Units Upgrades
 * Camel -> Heavy Camel
 * Bloodlines

Dock
Units
 * Fast Fire Ship
 * Elite Cannon Galleon

Monastery
Upgrades
 * Redemption
 * Block Printing
 * Illumination
 * Atonement
 * Theocracy

Siege Workshop
Units
 * Bombard Cannon

Blacksmith
Upgrades
 * Ring Archer Armor
 * Bracer
 * Plate Barding Armor

University
Upgrades
 * Architecture
 * Bombard Tower

Lumber Camp
Upgrades
 * Two-Man Saw

Mill
Upgrades
 * Crop Rotation