Appanage
In the parts of Europe where primogeniture prevailed, cadet sons were generally entitled to receive an appanage in patrimony, always substantially smaller than the eldest son's inheritance. Often, especially outside of Germany, the younger branch remained subordinate to the elder line as vassals or subjects.
Often, however, one or more younger sons were encouraged to take clerical orders, thereby forfeiting all rights of inheritance. Or a junior male might be encouraged to pursue a career in the military as an officer (e.g. Prince Eugene of Savoy, or as a courtier or civil servant in the monarch's capital.
Read more about this topic: Cadet Branch