The castle was originally built on the ground, from the ruins of another floating castle, the ancestral home of Rollondar e'Drien, which had fallen to its destruction when sorcery failed at the beginning of the Interregnum.
The structure was begun by Morrolan when he returned to the county of Southmoor from the Eastern village of Blackchapel. Since a nearby village, Nacine, had a large population of Vallista, Morrolan was able to call upon some very skilled artisans and laborers to design and build a temple dedicated to his goddess, Verra, in the area where the original castle's ruins were strewn.
During the ninth (or tenth) Battle of Dzur Mountain, Tazendra used Sorcery to raise the area of Morrolan's temple, which was still under construction. His Circle of Witches, led by Arra, then maintained its position in the air. This act of levitation effectively foiled Kâna's attempt to defeat Morrolan's army. It is somewhat unclear if Castle Black's levitation depends on the continuing efforts of his circle, which was apparently the case in the immediate aftermath of the battle, or if its state has since been made "permanent" in some fashion.
Castle Black was then finished during the first few years of Zerika the Fourth's reign, and the celebratory party of its completion is still in progress, with a variety of famous guests as well as some more unsavory ones.
Castle Black has served as a focal point for action in many of the stories we know about Dragaera. During the first day of the dedication party, Khaavren learned that Morrolan cared little for the three counties that Zerika had promised him but then retracted, a decision on the part of the young empress that had inspired the Tiassa to resign as Captain of the Guard. Mellar fled there after raiding the Jhereg treasury, in hopes that his death would bring down all three Houses he hated.
One curious aspect of Castle Black is the room in the highest tower. In that room can be found a variety of windows, whose number can appear to change, and which are portals to other places on Dragaera and sometimes even other worlds. Arra believed that this amazing room was a gift from Verra, given in appreciation of Morrolan's defeat and banishment of the rogue god, Tri'nagore.