Definition
Per infortunium (Latin: "by misadventure") is a classification of homicide in which a person, while engaged in a lawful act and without any intention to cause harm, accidentally causes the death of another. It is distinguished from other forms of homicide by the concurrence of two conditions: the actor was doing something legally permitted, and the death resulted from mischance rather than from design, recklessness, or negligence rising to criminal culpability. Under the older common law framework, homicide per infortunium was treated as excusable homicide — a category that, while technically a killing, was not punishable as a crime, though it historically could entail forfeiture of goods in early English law before that consequence was abolished by statute.
Common Confusion
Per infortunium is one of three traditional common law excusable or justifiable homicide categories that researchers frequently conflate:
- Homicide per infortunium (by misadventure): lawful act, no harmful intent, death accidental.
- Homicide se defendendo (in self-defense): death caused while resisting a threat, lawful but not truly accidental — the death is intentional in the narrow sense of being chosen as the means of defense.
- Justifiable homicide: death authorized by law (e.g., execution of a criminal sentence, killing in lawful war), carrying no criminal or civil disability.
The distinction matters in research because historical sources treat these three categories as a formal taxonomy. Misreading a source's category can lead to incorrect conclusions about whether a historical actor faced legal jeopardy.
Why It Matters in Research
The term is almost entirely a creature of historical common law and will not appear in modern statutory criminal codes. Researchers encountering it in primary sources — indictments, ecclesiastical records, coroners' inquests, and treatises from the medieval through early modern English period — should understand several navigational points.
First, per infortunium was the formal verdict or plea that triggered the "excusable homicide" track in English proceedings. A finding of per infortunium historically entitled the killer to a royal pardon as a matter of course, even though the killing was technically unlawful in the earliest periods. The pardon requirement was a procedural artifact, not a signal of guilt; many sources that list a pardon without explanation may be recording a per infortunium outcome.
Second, the doctrine's boundary with criminal negligence homicide is where the conceptual action is. The phrase "doing a lawful act" was the load-bearing requirement. If the act was unlawful — even a misdemeanor — the killing could not be per infortunium; it would be manslaughter or worse. This distinction anticipates the modern unlawful-act manslaughter doctrine and the misdemeanor-manslaughter rule. Researchers studying the evolution of manslaughter should treat per infortunium as a conceptual ancestor and trace the boundary carefully across sources.
Third, forfeiture. Early English law imposed forfeiture of goods even on excusable homicides including per infortunium. This was abolished by statute (33 Henry VIII and, more decisively, later enactments), but the abolition was gradual. Researchers working with financial records, estate inventories, or chancery proceedings should be alert to the survival of forfeiture practice in some periods despite the nominally excusable classification of the killing.
Fourth, Burrill notes a secondary pleading usage: the phrase "per infortunium" appeared in old Latin declaration forms to introduce the statement of special damage — the particular injury the plaintiff suffered as a consequence of the defendant's acts. This procedural usage is entirely distinct from the homicide classification and appears in civil, not criminal, records. Researchers working with early pleading forms should not import the homicide meaning into that context.
Historical Dictionary Support
All three source dictionaries agree on the core definition: homicide per infortunium is killing by misadventure during a lawful act, without harmful intent. All cite 4 Blackstone's Commentaries 182 as the authoritative textual home of the doctrine — a useful anchor, because Blackstone's treatment is the clearest synthesis of the common law position and the most likely source for how American courts and treatise writers received the concept.
Burrill's entry is the most detailed of the three. It adds the Fleta citation (lib. 1, c. 23, § 5), pushing the doctrine's textual pedigree into 13th-century English law, and it separately identifies the secondary civil pleading usage — a distinction the Black's entries omit entirely. Researchers relying solely on Black's would miss the pleading context and might misread a civil declaration.
No source engages meaningfully with the forfeiture history or the gradual statutory abolition, which is a significant gap for anyone working with pre-19th-century English or early American records. The dictionaries also do not address how American jurisdictions received or discarded the category as they codified criminal law, leaving researchers to trace that reception independently through treatises such as those of Joel Bishop or Francis Wharton on criminal law.
Jurisdictional Note
Per infortunium as a formal legal category belongs to English common law and American common law inherited from it. American criminal codes replaced the excusable/justifiable homicide taxonomy with statutory frameworks that do not use this Latin terminology. In research involving colonial American or early state court records, the doctrine may appear by name; in modern American materials, it surfaces only in historical analysis or academic commentary.
Encyclopedia Cross-Reference
None of the matching encyclopedia entries address per infortunium or its immediate doctrinal context. No cross-reference recommended.