The term was originally Merovingian and referred to property that was inherited rather than purchased. Over time though, as the ideas of lordship and vassalage became more common and more entangled with fief-holding, “allod” begand to refer to land and other property owned outright, whether inherited or purchased.* A fief technically still belonged to the lord rather than the vassal, though it was the vassal who had control over it.
Though inheritance of fiefs became more and more common over time, it was not a given and the lord could entrust the position and the land to someone else if they wished to. An allod, by contrast, belonged to and was controlled by the person who owned it. Taxes on such property were lesser or nonexistent, and one could sell or donate it without asking permission from anyone. Since an allod was simply property and not also a position, it could also be divided for inheritance purposes and/or left directly to a daughter without her having to marry someone who would then take the oath of fealty and become the lord’s vassal.
The ownership of allodial land was not limited to only the upper classes who could participate in the vassal-lord contract. It was widespread among the lower classes as well and significant number of peasants owned the land they worked themselves.
Owning land in this way allowed for a lot more independence. Holding land in fief could grant or maintain political connections, whereas allodial land granted resources, came with no strings attached, and had far fewer restrictions on inheritance.** Matilda of Tuscany was able to wield the power she did because of her vast amount of allodial land.*** Peasant allodists owed no rent or service to anyone, leaving them with far more freedom and resources. Allodial property added a layer of complexity to the lord-vassal system, granting a certain level of independence from social ties, but on its own, isolating the property owner from those same ties.
**Especially since a fief did not necessarily go to the vassal’s heir, particularly in earlier centuries.
***Also, the Dutch House of Orange is so named because Orange was the only land William I owned in his own right rather than in fief to somebody else.
Bouchard, Constance Brittain. Strong of Body, Brave & Noble: Chivalry & Society in Medieval France. Ithaca, NY: Cornell University Press, 1998.
Hodder, Michael J. "Allod." In Dictionary of the Middle Ages v.1, edited by Joseph R. Strayer, 190. New York: Charles Scribner's Sons, 1982.
Stephenson, Carl and Bryce Lyon. Mediaeval History: Europe from the Second to the Sixteenth Century. New York: Harper & Row, 1962.
Allod - Wikipedia