The tech tree from early access builds 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 (80 Science)
Technology
Prerequisites
Total Science Required
Effects
Ironworking
None
80
Stonecutting
None
80
Trapping
None
80
Divination
None
80
Administration
None
80
Tier 2 (120 Science)
Technology
Prerequisites
Total Science Required
Effects
Labor Force
Ironworking
200
Husbandry
Ironworking
200
Drama
Stonecutting
200
Polis
Stonecutting, Trapping
280
Trapping
Military Drill
200
Aristrocracy
Divination
200
Sovereignty
Divination, Administration
280
Rhetoric
Administration
200
Tier 3 (200 Science)
Technology
Prerequisites
Total Science Required
Effects
Navigation
Labor Force
400
Phalanx
Labor Force
400
The Wheel
Husbandry
400
Ramparts
Drama
400
Forestry
Polis
480
Battleline
Military Drill, Ironworking
480
Monasticism
Aristocracy
400
Composite Bow
Rhetoric
400
Metaphysics
Rhetoric
400
Tier 4 (400 Science)
Technology
Prerequisites
Effects
Citizenship
Phalanx
Drawbridge
Ramparts
Land Consolidation
Forestry
Steel
Forestry, Battleline
Doctrine
Monasticism, Metaphysics
Siegecraft
Sovereignty
Tier 5 (800 Science)
Technology
Prerequisites
Effects
Coinage
Navigation
Scholarship
Citizenship
Torsion
Phalanx, Siegecraft
Stirrups
Spoked Wheel, Land Consolodation
Architecture
Drawbridge
Manor
Land Consolodation, Composite Bow
Machinery
Siegecraft
Mounted Archery
Siegecraft
Cartography
Metaphysics, Navigation
Tier 6 (1600 Science)
Technology
Prerequisites
Effects
Hydraulics
Coinage
Lateen Sail
Scholarship
Warrior Code
Architecture
Bodkin Arrow
Steel
Aesthesics
Doctrine, Architecture
Unit Tactics
Doctrine
Strategy
Cartography, Torsion
Tier 7 (3200 Science)
Technology
Prerequisites
Effects
Vaulting
Hydraulics, Aesthetics
Jurisprudence
Lateen Sail
Barding
Stirrups, Warrior Code
Sarissa
Bodkin Arrow, Citizenship
Fiscal Policy
Unit Tactics, Machinery
Windlass
Mounted Archery, Strategy
Tier 8 (6400 Science)
Technology
Prerequisites
Effects
Economic Reform
Jurisprudence
Military Reform
Sarissa
Political Reform
Fiscal Policy
