In Roman law, any ‘acquisition mortis causa ’not based on succession or legacy (Inheritance law III. H.): (1) gift mortis causa ( donatio ); what someone (2) received in fulfilment of a condition of a will or (3) on the condition that a third party (not the executing party) would die, or in exchange (4) for waiving an acquisition under inheritance law or (5) for an application for provisional safeguarding of an estate in favour of an unborn child ( missio in possessionem ) (Dig. 39,6,38; 31 pr./2; 8 pr.; 12).
Kaser, RPR 1, 765; 2, 567