Buildings/Siege Workshop

The Siege Workshop is a building that allows for the training and upgrade of siege units. It is the fourth troop training building unlocked, along with the (infantry),  (archer units), and  (cavalry units).

Five tiers of siege units are available to train once unlocked through research, each with increasing time and resource requirements. Existing units can be upgraded by one tier at a time, though at greater overall resource cost than training the higher tier directly.