Definition
Legatum optionis is a Roman law concept referring to a testamentary bequest that grants the legatee the right to choose or select one or more items from the testator's estate. Rather than specifying a particular object, the testator confers on the named beneficiary the personal power of selection — the legacy is defined by the legatee's exercise of choice.
The defining characteristic is the personal nature of the optio: the right of selection was historically understood as inherently tied to the named legatee and could not be transmitted to that person's heirs or representatives. If the legatee survived the testator but died before exercising the choice, the legacy lapsed entirely under classical Roman law, because the power to elect was considered personal and non-delegable.
Justinian reformed this rule. Under Justinianic law, if the legatee died after the testator without having made the selection, the legatee's representative (hæres) was permitted to make the selection on behalf of the deceased legatee's estate, preserving the legacy rather than extinguishing it.
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Common Confusion
Legatum optionis should not be confused with the common law doctrine of election in wills, which requires a beneficiary to choose between accepting a testamentary benefit and asserting a competing right inconsistent with the will. That doctrine is distinct in origin, structure, and operation. The Roman concept concerns the power to select an object from the estate; the common law doctrine concerns a choice between legal positions. The surface similarity — both involve a legatee making a choice — can mislead researchers working across legal traditions.
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Why It Matters in Research
This term appears almost exclusively in sources treating Roman law or in discussions of civil law inheritance doctrine. Researchers are unlikely to encounter legatum optionis in common law primary sources, but it surfaces in three contexts:
First, in treatises on Roman and civil law succession, where it is used to illustrate the personal character of certain testamentary rights and the broader principle that a right conditioned on personal election may not automatically transmit to heirs.
Second, in comparative law scholarship examining how Justinian's reforms shaped later civil law traditions, particularly in jurisdictions with Roman law roots — Louisiana, Quebec, Scotland, and South Africa among them. The Justinianic modification is frequently cited as an early instance of legislative intervention to prevent a right's lapse on purely technical grounds.
Third, as a historical reference point in discussions of elective legacies in Anglo-American equity. English and American courts occasionally looked to Roman categories when addressing testamentary gifts conditioned on a beneficiary's election, though the common law doctrine of election in wills developed along its own independent path and should not be conflated with legatum optionis.
Researchers using nineteenth-century legal dictionaries should be alert to the truncated definitions in most sources — the Black's and Rapalje & Lawrence entries break off before completing the description of Justinian's rule, which is the more practically significant half of the doctrine. Confirm the full rule in primary Roman law sources or secondary treatises on Roman private law.
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Historical Dictionary Support
Black's Law Dictionary (1st and 2nd editions) and Rapalje & Lawrence provide virtually identical entries, all derived from a common tradition. All three sources correctly identify the two-stage structure of the doctrine — the classical rule of lapse and the Justinianic reform — and all three entries appear to share the same truncated text, cutting off before fully stating what Justinian's reform authorized the representative to do. This shared truncation suggests a common source text and is a known limitation of these entries.
None of the three dictionaries offer any discussion of how this concept maps onto later civil law systems or onto common law doctrine. They treat the term purely as a Roman law artifact, which is historically accurate but leaves the researcher without guidance on its downstream significance.
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Jurisdictional Note
Legatum optionis is a doctrine of Roman law and has no direct counterpart in the common law of wills. Civil law jurisdictions — particularly those in the Romanist tradition — may recognize analogous constructs under their codes of succession, but the specific term and its classical contours belong to the study of Roman private law rather than to any modern national system as such.
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