The inheritance customs in the Seven Kingdoms are vague, uncodified, and subject to varying interpretations. Male-preference primogeniture is customary, but not binding. The eldest son of a man is his heir, followed by his younger sons. A man's daughters are set to inherit before a man's brothers. The only exception is Dorne, where the inheritance laws are based on Rhoynish customs. As such, inheritance in Dorne is based on the order of birth, and not the gender of the child. However, regardless of the firstborn male-preference, Lords can choose to name a younger child as their heir, or the child of another. When there is no clear heir, a widow might lay claim on the lands. Claims might also be presented to a lord's liege. Bastards cannot inherit unless they are legitimized. Yet, even when they are legitimized, it is not clear whether they join the line of succession in order of birth, or simply come after all trueborn children.
Inheritance customs regarding the inheritance of the Iron Throne during the Targaryen dynasty differs from regular customs. While at first female inheritance did not seem problematic, the issue was raised when King Jaehaerys I Targaryen's eldest son, Prince Aemon, died. Aemon's only child was a daughter named Rhaenys, but instead of naming Rhaenys as the new heiress to the throne, King Jaehaerys I chose his next eldest son, Prince Baelon. Following Baelon's death, a Great Council was called in which the Westerosi lords voted on the succession. The two biggest contenders were Rhaenys's son Laenor and Baelon's son Viserys. Though Laenor descended from the senior line, the lords felt that a male line was preferred over a female line, and believed that a precedent was set stating that the Iron Throne could not pass to a woman, or to her male descendants. Ironically, after ascending the throne, Viserys himself later disregarded these precedents by naming his daughter Rhaenyra as his heir despite having three healthy sons by a second marriage. This decision eventually led to the civil war known as the Dance of the Dragons.
Regardless, female claims have since been considered on several other occasions. Read more...