Definition
In medieval English law, purgatio referred to a formal process of clearing oneself of a charge or accusation — a legal or ecclesiastical mechanism by which an accused person established innocence through prescribed ritual, oath, or ordeal rather than through adversarial fact-finding. The term is Latin, derived from purgare (to cleanse or purge), and carries the literal sense of a cleansing from suspicion or guilt.
Two principal forms appear in the historical sources:
1. Purgatio vulgaris (common or vulgar purgation): Clearance of accusation through physical ordeal — trial by fire, water, or combat. Abolished in England following the Fourth Lateran Council (1215), which withdrew ecclesiastical support for ordeals.
2. Purgatio canonica (canonical purgation): An ecclesiastical procedure in which the accused denied the charge under oath, supported by a required number of compurgators (oath-helpers) who swore to the credibility of the accused. This form survived longer, particularly in church courts, and has a direct relationship to the common law procedure of compurgation (wager of law).
Common Confusion
PURGATIO is frequently encountered as a genus term covering both ordeal-based and oath-based clearance, but researchers should not treat the two subtypes as interchangeable. Purgatio vulgaris was condemned and discontinued by the church; purgatio canonica endured in ecclesiastical jurisdiction and influenced secular wager of law well into the early modern period. Conflating the two produces errors when tracing the abolition of one form versus the survival of the other.
PURGATIO should also be distinguished from ABSOLUTIO. Purgatio was a procedural mechanism for clearing suspicion before or during trial; absolutio was a formal verdict or discharge following completed proceedings. The cleansing metaphor in purgatio signals process, not outcome.
Recognized Forms
/SUBTYPES
Purgatio vulgaris — Clearance by physical ordeal (fire, water, combat). Associated with pre-Lateran IV practice. Effectively ended in English ecclesiastical and royal courts in the thirteenth century.
Purgatio canonica — Clearance by sworn denial supported by compurgators. The canonical form recognized by church courts. Persisted in ecclesiastical jurisdiction and influenced the common law institution of wager of law (law vadium).
Why It Matters in Research
Researchers working in medieval English legal sources will encounter purgatio as both a standalone term and as a prefix in compound Latin phrases. The key navigational challenge is that English legal historians did not always distinguish the two subtypes consistently; some early modern legal writers used purgatio to mean canonical purgation specifically, having already treated vulgar purgation as a historical curiosity.
In Fleta (the thirteenth-century legal treatise Burrill cites at lib. 4, c. 18, § 1), purgatio appears in the context of specific procedural contexts where the cleansing metaphor is technical, not rhetorical. Researchers using Fleta or Bracton should note that these sources predate the full consolidation of canonical purgation doctrine and may describe transitional practices.
Connections to compurgation are essential. In English common law corpus materials, purgatio canonica and compurgation are functionally synonymous, but purgatio more often appears in ecclesiastical and civilian-influenced sources while compurgation dominates the common law narrative. A researcher tracing wager of law through Year Books and into Blackstone will find the concept migrating from Latin purgatio terminology into English procedural vocabulary.
Historical trap: The ecclesiastical version of purgatio survived in English church courts until the seventeenth century and was formally abolished by statute (Ecclesiastical Courts Act 1661 addressed related matters; the procedure's demise is traced variously in different sources). Do not assume purgatio disappeared when vulgar purgation was condemned in 1215.
Historical Dictionary Support
Burrill's Law Dictionary offers only a minimal entry, defining purgatio as "a cleansing or scouring" and citing Fleta lib. 4, c. 18, § 1 without elaboration on the subtypes or their procedural mechanics. The entry is useful as a pointer to Fleta but provides no analytical framework for distinguishing vulgaris from canonica forms.
Burrill's entry reflects a common limitation of nineteenth-century legal dictionaries when handling medieval Latin procedural terms: they provide the philological root and a primary source citation but leave the practitioner or historian to reconstruct the doctrine from treatise sources independently. Researchers should treat Burrill's purgatio entry as a finding aid to Fleta rather than a complete account.
For fuller treatment, the ecclesiastical law literature — particularly sources addressing church court procedure — supplements what the common law dictionaries omit. The canonical purgation procedure was elaborated in decretal law and commentaries on the Decretum of Gratian, sources outside the ordinary scope of English law dictionaries of Burrill's period.
Jurisdictional Note
Purgatio as a live procedural term is entirely historical in all modern common law jurisdictions. Its relevance is confined to medieval and early modern English law, ecclesiastical court practice, and comparative legal history. Researchers working in canon law or civilian traditions may encounter the term in a somewhat broader temporal range than in English common law sources.