Keep is a University technology.
- Building: University
- Age: Imperial Age
- Cost: 500 food, 350 wood
- Research time: 75 seconds
- Available to: 37 of 56 civilizations (19 do not have it).
Upgrades Guard Towers to Keeps, the strongest version of the tower line.
Figures from the game data for Update 185872 (September 2026), at the time of publishing.