Primogeniture

Primogeniture (/ˌpraɪməˈdʒɛnɪtʃər, -oʊ-/) is the right, by law or custom, of the firstborn legitimate child to inherit all or most of their parent's estate, as well as succeed their parent as the ruler of a state.

Primogeniture stands in contrast to shared inheritance among all or some children, any illegitimate child or any collateral relative. In most contexts, it means the inheritance of the firstborn son (agnatic primogeniture). It can also mean by the firstborn daughter (matrilineal primogeniture), or firstborn child (absolute primogeniture).

Research shows that authoritarian regimes that rely on primogeniture for succession were more stable than forms of authoritarian rule with alternative succession arrangements. Scholars have linked primogeniture to a decline in regicide, as clear rules of succession reduce the number of people who could (absent a coup d'état) replace a ruler, thus making it less desirable to cause the death of the monarch.