A cadet branch consists of the male-line descendants of a monarch's, ruler's or patriarch's younger sons (cadets). In the ruling dynasties and noble families of much of Europe and Asia, the family's major assets (realm, titles, fiefs, properties, lands and income) have historically been passed from the father to his firstborn son in what is known as primogeniture; younger sons, the cadets, generally inherited less wealth and authority (such as a small appanage) to pass on to future generations of their descendants.
In families and cultures in which that was not the custom or law, such as the feudal Holy Roman Empire, the equal distribution of the family's holdings among male members was eventually apt to so fragment the inheritance as to render it too small to sustain the descendants at the socio-economic level of their forefather—and indeed, too small to efficiently manage or effectively defend. Moreover, brothers and their descendants sometimes quarreled over their allocations, or even became estranged. While agnatic primogeniture became a common way of keeping the family's wealth intact and reducing familial disputes, it did so at the expense of younger sons and their descendants. Both before and after a state legal default of inheritance by primogeniture, younger brothers sometimes vied with older brothers to be chosen as their father's heir or, after the choice was made, sought to usurp the elder's birthright.
