The tech tree Techs (short for "technologies") are empire upgrades that cost science and provide various benefits and make additional techs and some laws and events available.
Tier 1 (100 Science)
Technology
Prerequisites
Leads To
Effects
Ironworking
None
Husbandry, Labor Force, Steel (with Military Drill)
Warrior
Stonecutting
None
Fort, Quarry
Trapping
None
Slinger, Camp
Divination
None
Aristocracy
Shrine
Administration
None
Rhetoric, Free Worker
Treasury, Granary
Tier 2 (150 Science)
Technology
Prerequisites
Leads To
Effects
Labor Force
Ironworking
Navigation, Phalanx
Roads, Slavery / Freedom, Revelation
Husbandry
Ironworking
Spoked Wheel, Food Boost
Pasture
Drama
Stonecutting
Portcullis (with Spoked Wheel), Free Settler
Odeon, Gnosticism
Polis
Stonecutting, Trapping
Military Drill
Trapping
Composite Bow, Steel (with Ironworking)
Barracks, Rally Troops
Aristocracy
Divination
Border Boost, Sovereignty (with Rhetoric), Monasticism
Ambassador, Centralization / Vassalage
Rhetoric
Administration
Border Boost - All Cities +6 Border Tiles
Food Boost - +200 Food
Tier 3 (250 Science)
Technology
Prerequisites
Leads To
Effects
Navigation
Labor Force
Phalanx
Labor Force
Spoked Wheel
Husbandry
Forestry
Polis
Land Consolidation, Free Court Scholar, Free Heavy Chariot, Free Light Chariot
Lumbermill, Enlightenment
Steel
Military Drill, Ironworking
Sovereignty
Aristocracy, Rhetoric
Metaphysics
Rhetoric
Cartography (with Navigation)
Convert to State Religion, High Synod, Archive I, Redemption,
Tier 4 (400 Science)
Technology
Prerequisites
Leads To
Effects
Coinage
Navigation
Money Boost, Lateen Sail (with Cartography)
Market, Pacify City, Automate Workers
Citizenship
Phalanx
Scholarship, Stirrups (with Spoked Wheel), Free Court Minister
Courthouse, Divine Rule / Legal Code
Portcullis
Drama
Land Consolidation
Forestry
Cohorts (with Battle Line), Manor (with Composite Bow), Free Camel Archer, Free War Elephant
Camel Archer, War Elephant, Grove
Composite Bow
Military Drill
Manor (with Land Consolidation), Free Akkadian Archer, Free Archer, Free Palton Cavalry
Archer, Range
Monasticism
Aristocracy
Doctrine
Monastery, Monotheism / Polytheism
Machinery
Sovereignty
Hydraulics, Free Onager
Onager
Tier 5 (600 Science)
Technology
Prerequisites
Leads To
Effects
Scholarship
Citizenship
Stirrups
Citizenship, Spoked Wheel
Architecture
Portcullis
Vaulting, Free Siege Tower
Bath, Philosophy / Engineering
Manor
Composite Bow, Land Consolidation
Bodkin Arrow, Goods Boost, Free Turreted Elephant
Conscript, Professional Army / Volunteers
Battle Line
Phalanx, Steel
Barding (with Martial Code), Cohorts (with Land Consolidation), Free Court Soldier
Maceman
Doctrine
Monasticism
Temple, Tolerance / Orthodoxy
Hydraulics
Machinery
Windlass (with Scholarship), Ballistics (with Cartography), Free Ballista
Ballista, Mill
Cartography
Metaphysics, Navigation
Lateen Sail (with Coinage), Ballistics (with Hydraulics)
Trireme, Harbor, Steal Research
Goods Boost - +400 Iron, +400 Stone, +400 Lumber
Tier 6 (1000 Science)
Technology
Prerequisites
Leads To
Effects
Lateen Sail
Cartography, Coinage
Fiscal Policy (with Jurisprudence), Free Dromon
Dromon, Autarky / Trade League
Jurisprudence
Scholarship
Fiscal Policy (with Lateen Sail), Free Court Minister
Insurrection, Guilds / Elites
Martial Code
Stirrups
Barding (with Battle Line)
Towers, Pilgrimage / Holy War
Vaulting
Architecture
Bodkin Arrow
Manor
Infantry Square, Free Longbowman, Free Cimmerian Archer
Longbowman
Windlass
Torsion
Tier 7 (1500 Science)
Technology
Prerequisites
Leads To
Effects
Fiscal Policy
Lateen Sail, Jurisprudence
Economic Reform, Free Court Merchant
Coin Debasement / Monetary Reform
Barding
Steel, Martial Code
Military Prestige (with Infantry Square and Cohorts)
Cataphract
Infantry Square
Bodkin Arrow
Military Prestige (with Barding and Cohorts), Free Court Soldier, Free Phalangite
Pikeman
Cohorts
Land Consolidation, Battle Line
Military Prestige (with Barding and Infantry Square), Free Legionary
Swordsman
Chain Drive
Windlass
Industrial Progress (with Ballistics)
Polybolos
Ballistics
Hydraulics, Cartography
Industrial Progress (with Chain Drive)
Mangonel
Tier 8 (2000 Science)
Technology
Prerequisites
Leads To
Effects
Economic Reform
Fiscal Policy
Court Merchant, +1 Victory Point
Military Prestige
Barding, Infantry Square, Cohorts
Court Soldier, +1 Victory Point
Industrial Progress
Chain Drive, Ballistics
Court Minister, +1 Victory Point
All Tier 8 technologies can be researched multiple times
