The prequel series shows the Targaryen dynasty ruling over 15 dragons at its peak. From such heights, most empires fall. King Viserys Targaryen's decision to name Rhaenyra successor to the Iron Throne almost 193 years before Game of Thrones begins the Targaryens' long decline. After Viserys fathers a son, the court is shocked when Rhaenyra remains his heir, sowing conflict across the realm.