This paper presents the evolution of the institution of legitime a.k.a. reserve (forced heirship) in the law of Louisiana as an universal example that applies also to Polish debates concerning the law of succession. The description of this evolution is focused mainly on the issue of the clashing of two legal traditions. The growing influence of common law on the civil legal system of Louisiana first led to radical reaction against changes in succession law, which had its culmination in introduction of constitutional protection of forced heirship in 1921. After long debates and political struggles the situation was at least technically reversed when another constitutional amendment was passed in 1995, prohibiting the forced heirship with an exception for juvenile or handicapped children of the testator. The paper discusses that historical argument has been extremely important in this process and the Louisiana's lawyers are deeply concerned with the question about their legal heritage. The conclusion underlines that such a question should be asked also in the ongoing debate of Polish lawyers on the future of the institution of legitime.