Agnatic Primogeniture
One's agnate may be male or female provided that the kinship is calculated patrilineally; i.e., only through males back to a common ancestor. "Agnatic primogeniture" or "patrilineal primogeniture" is inheritance according to seniority of birth among the sons of a monarch or head of family, with sons and their male issue inheriting before brothers and their issue. Thus, inheritance could be traced through the male line only, to the complete exclusion of females. This is commonly referred to as the Salic law (see Terra salica).
By the beginning of the 19th century, only the royal houses of Bourbon and Savoy, among Europe's historic national dynasties, continued to exclude women from succession. Later, the new monarchies or dynasties of France (under the Bonapartes), Belgium, Denmark (from 1853), Sweden (from 1810), and the Balkan realms of Albania, Bulgaria, Montenegro, Romania, and Serbia introduced Salic law. During this era, Spain and Portugal fought civil wars which pitted the Salic and female-line heirs of their dynasties against one another for possession of the crown.
Most British and French titles of nobility descend to the senior male by primogeniture, to the exclusion of females, and agnatic cadets may bear courtesy titles.
A variation on Salic primogeniture allows the sons of women to inherit, but not women themselves, an example being succession to the throne of Spain from 1947–1978. This is the law in Liechtenstein and in the former Archduchy of Austria.
Read more about this topic: Primogeniture, Variations