The Stonemason building gives you a defensive bonus against catapults for your buildings. It can only be built in the capital city. Each level of the Stonemason gives you between 2 and 3% defensive bonus to the hitpoints of your buildings.
- Mongols: 2.5% bonus for each level built
- Papal State: 2% bonus for each level built
- Hanseatic League: 2.5% bonus for each level built
- Valachia: 3% bonus for each level built
Levels: 20
Requirements: Fortress lvl 20
Costs for lvl 1:
- Wood: 2,560
- Iron: 3,800
- Stone: 3,200
- Gold: 1,150