Building of the Medieval Era Production Cost 225 File:Civ6Production.png Faith Cost File:Civ6Faith.png Gold Cost File:Civ6Gold.png Maintenance 0 File:Civ6Gold.png Technology Image:Castles (Civ6).png Castles District Image:City Center (Civ6).png City Center Required infrastructure Effect +50 Outer Defense Strength +2 File:Housing6.png Housing under the Monarchy Government. Medieval Walls are a defensive structure of the Medieval Era in Civilization VI. They are built in the City Center and require Ancient Walls.