Revolution
The time that the warforged rebelled against their giant slavers.
The warforged, after being taken as a slave race and being forced to serve in the Giant Crusades, rebelled against their slavers: The Giants. They united under a banner of freedom, and after the first group revolted, the rest of the race soon followed. Pretty soon, the dragonborn allied with the warforged in order for both sides to help the other gain freedom.