|Overview||Chronicles tech tree||Warbirth tech tree|
The Foundry is a vital building as it is involved in the smelting and production of Metal for your nation. As it is somewhat costly and also quite difficult to unlock, you should build one as soon as possible, preferably in whichever city you control which has the most capacity for Metal production, ie one city with enough room for 10 miners as opposed to a city with 3 mines but a combined capacity of only 5.
In Chronicles, it is essential to research the Logistics upgrades as quickly as possible, as the first two rungs of the upgrade track are vital for unlocking upgrades associated with Woodworking. There is a greater impetus in the Imperial Era to complete both Metallurgy and Logistics tracks for the Holy Roman Empire as the last upgrades for both are required to create the Reichsritter.
In Warbirth, Metallurgy upgrades gain a greater significance especially during the Axial Age, as Ironworking is required for many powerful late-game units.