Agnatic primogeniture is inheritance by the first-born male child. Cognatic primogeniture is inheritance by the first-born child without regards to gender. The first country to adopt full cognatic primogeniture was Sweden in 1980. Beneficiary of this was Victoria of Sweden.
A special case of primogeniture exemplified in the French royal milieu, the Salic Law (attributed to the Salian Franks) forbade any inheritance of a crown through the female line. This accounts for the separation of the royal house of Luxemburg from that of the Netherlands, and partially explains the role of Carlism in Spain.