A Preceding Note:

I do enjoy studying law and legal philosophies from time to time, but I'm not a legal student here or even in the legal sectors, so please try to put any explanation you have into (some degree of) layman's terms.

The Question, Main Source:

I stumbled onto this article on Wikipedia about the legal concepts in ancient Roman law of "adrogation" and "arrogation".

It defined the former as a sui juris adoption of another person, and the latter as an alieni juris adoption of another person.

Adrogation, among ancient Romans, was a kind of adoption in which the person adopted was free, and consented to be adopted by another. It was done at the assembly of the people while the commonwealth subsisted, and later by a rescript of the emperors.

This is contrasted with arrogation, in which one claims another for oneself without the right.

But it only referenced a single source¹, and it wasn't one I have really heard of, so I decided to check other sites to verify.

Other Sources

  1. Oxford Dictionaries Online (ODO) defined "adrogation" as sui juris and "arrogation" as alieni juris.


Adoption of a person who is sui juris and hence not subject to the legal power of another.


Take or claim (something) without justification

  1. Oxford English Dictionary (OED)² defined "adrogation" as sui juris and "arrogation" as both(???) alieni juris and a synonym of arrogation. (How the scrambled eggs can it be both sui juris AND alieni juris???)


Adoption of a person who is sui juris (sui juris n. a) and hence not subject to the legal power of another. Cf. arrogation n. 1.


  1. = adrogation n. (So usually spelt in this sense.)

  2. The action of claiming and assuming without just reason; unwarrantable assumption.

  1. Merriam-Webster Online defines "adrogation" as a synonym of "arrogation" (basically the exact opposite of what the ODO did), which is defined as alieni juris.


: arrogation 2


: to take or claim (something, such as a right or a privilege) in a way that is not fair or legal

So which is it? It can't be both sui juris and alieni juris adoption.

I'm so confused... @_@

¹ Here is the source the Wikipedia article cited:

[Public Domain Symbol] This article incorporates text from a publication now in the public domain: Chambers, Ephraim, ed. (1728). "article name needed". Cyclopædia, or an Universal Dictionary of Arts and Sciences (first ed.). James and John Knapton, et al.

² These require a paying subscription, so I'll just include the links down here so as not to mislead anyone.

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