Definition
In old English law, misfortune, misadventure, or mischance. The term appears principally in the phrase *homicide per infortunium* — killing by misfortune — which described an unintentional killing occurring in the course of a lawful act, without negligence and without any intent to harm. The actor neither sought to cause death nor was acting unlawfully when death resulted. Infortunium as a standalone term is largely vestigial in modern legal usage; its enduring significance is almost entirely through its compound phrase.
Common Confusion
INFORTUNIUM vs. NEGLIGENCE vs. CHANCE MEDLEY: These three concepts occupied distinct positions in early English homicide taxonomy and are easily collapsed by modern readers. Infortunium described pure misfortune during a lawful act — no fault, no intent. Negligence (or *culpable misadventure*) involved a lawful act performed carelessly, carrying moral and sometimes legal blame. Chance medley (*chaud medley*) described an accidental killing during a sudden affray — unlawful in its setting but unpremeditated in its outcome. Conflating them distorts both the historical legal analysis and the gradations of culpability that early common law took seriously.
Why It Matters in Research
Researchers encountering *infortunium* in historical English legal sources are almost always dealing with homicide classification, not a freestanding doctrine. The term matters in two primary ways.
First, early common law drew sharp taxonomic lines among forms of killing: murder, manslaughter, homicide per infortunium, and homicide se defendendo (in self-defense). These categories carried different legal consequences — most critically, whether the actor forfeited goods to the crown. Homicide per infortunium, like se defendendo, historically required a royal pardon even though no moral guilt attached, and the actor's goods were subject to forfeiture under early practice. This is a counterintuitive result for modern researchers who expect legal innocence and practical consequence to align.
Second, the forfeiture rule attached to infortunium changed over time. The Statute of Gloucester (1278) and subsequent developments gradually softened the harshest consequences, and by Blackstone's era the doctrine had evolved further. Researchers using Bracton, Fleta, or Britton will encounter the strict early framework; researchers using later authorities will find a more relaxed treatment. Failing to note which period's sources are being consulted will produce anachronistic readings of culpability.
For corpus researchers, *infortunium* functions as an indexing term pointing toward the broader cluster of misadventure materials. Fleta, Book I, Chapter 31 — cited by Burrill — is the principal primary anchor. Cross-referencing against entries for homicide, pardon, and forfeiture in the Law Mind corpus will surface the doctrinal network this term inhabits.
Historical Dictionary Support
Burrill is the primary historical dictionary source for this term, and his treatment is brief but precise: Latin derivation (in- privative + fortuna), translation as misfortune/misadventure/mischance, and a direct citation to Fleta. He does not elaborate on legal consequences, treating the term as essentially definitional shorthand for the compound phrase. The brevity is telling — by the time Burrill compiled his dictionary, *infortunium* had receded from active use and survived mainly as a term of art in historical and academic legal discussion.
What Burrill's entry does not capture is the doctrinal weight the term once carried. Early treatise writers — Bracton in particular — used the infortunium/se defendendo/murder tripartite framework as the organizing structure for criminal homicide analysis. The concept that a blameless actor still required a pardon, and still risked forfeiture, reflects a pre-modern legal logic in which social consequences attached to the act itself, not solely to the actor's moral state. Modern dictionaries tend to gloss this over; researchers consulting only later authorities may not encounter the full severity of the earlier rule.
No significant divergence among historical sources on the core definition: the term consistently means misfortune or mischance in the context of unintentional killing. The evolution is in consequence, not meaning.
Jurisdictional Note
*Infortunium* is a term of English common law with no meaningful independent life in American or other common law jurisdictions. American courts and statutes absorbed the underlying concept into involuntary manslaughter doctrine and excusable homicide without retaining the Latin terminology. Researchers working in Scottish, Irish, or colonial legal materials should verify whether local practice followed the English framework, particularly regarding forfeiture consequences.
Encyclopedia Cross-Reference
Law Mind Encyclopedia — Homicide (Excusable and Justifiable); Misadventure; Forfeiture at Common Law