Fidei Commissum Law and Legal Definition

Fidei commissum is the devise of property, with the prohibition against its alienation, when made with a view to a purpose. In the case of a fidei commissum, the first legacy is not avoided if the trust, or fidei commissum, be to a third party for the benefit of the second, or substituted legatee, and distinct from the first legacy.

The fidei commissum of the civil law is not identical with the trust of the common law. The former, under the simple jurisprudence of the Romans, was a direction to the legatee to convey the property itself, or a part of it, in full ownership to the intended beneficiary; whereas the latter is a refinement, by which the perfect ownership is decomposed into its constituent elements of legal title and beneficial interest, which are vested in different persons. But the term "fidei commissum" is constantly translated into the word "trust". [McDonogh v. Murdoch, 56 U.S. 367 (U.S. 1854)].