What is “primogeniture” in medieval inheritance practice?

The story behind the answer

Primogeniture was the custom by which the firstborn male inherited the family’s title and main estate. Feudal society favored it because keeping land intact ensured a single, powerful lord could meet military and financial obligations to his overlord, rather than fragmenting a fief among multiple heirs.

It became especially prominent in Western Europe from the 11th century, notably in Normandy and then England after 1066. In contrast, some regions used partible inheritance (dividing land among sons) or, more rarely, ultimogeniture (youngest inherits). Primogeniture had major social effects: younger sons often sought careers in the Church, the military, or royal administration, or joined ventures like the Crusades. While daughters could inherit in the absence of sons, male preference dominated, and disputes over succession fueled dynastic politics and occasional wars.