Definition
A Latin term with two distinct legal meanings in historical English and feudal law:
1. (Ecclesiastical and common law) An infidel or heathen — a person outside the Christian faith. The term carried legal consequence in medieval and early English law, where religious status could affect a person's capacity to take oaths, testify in court, or claim certain legal protections.
2. (Feudal law) One who violated fealty — a vassal or subject who broke the oath of fidelity owed to a lord. In this sense, infidelis does not describe religious standing but faithlessness to a feudal obligation, and was used to designate a person who had betrayed the bond of tenure that structured feudal relationships.
Common Language
Modern common usage (Wiktionary): "Infidel" — a person who does not believe in a particular religion, especially as viewed by those who do; an unbeliever.
Historical common usage (Webster's 1913): "Infidel" — one who does not believe in the prevailing religion; one who denies the divine origin of Christianity; an unbeliever.
The gap between common and legal usage is significant. In ordinary language — then and now — "infidel" is purely a descriptor of religious status. In feudal law, infidelis carried a second, technically distinct meaning tied to oath-breaking and breach of fealty that has no counterpart in the common usage of "infidel." A researcher encountering the term in a feudal document cannot assume the religious meaning applies.
Common Confusion
The two meanings of infidelis can easily be conflated in historical sources, and context is essential to distinguishing them. A document invoking infidelis in a church or excommunication context almost certainly uses it in the religious sense. A document arising from feudal tenure, oath-taking, or a dispute between lord and vassal almost certainly uses it in the faithlessness sense. The confusion is compounded because both meanings share an underlying concept of violated faith — religious in one case, sworn obligation in the other — and historical writers did not always cleanly separate them.
Why It Matters in Research
Researchers working in medieval English legal sources, feudal records, or ecclesiastical materials will encounter infidelis in both senses, sometimes within the same corpus. The critical navigational point is that the term's legal weight changed depending on the forum: in canon law and ecclesiastical proceedings, infidelis described status and triggered consequences around testimony and excommunication; in feudal records, it described conduct — specifically the violation of the oath of fealty — and triggered consequences around forfeiture or loss of lordly protection.
The phrase inter infideles connumerare, preserved in Burrill citing Cowell, is particularly useful as a fixed legal expression meaning to excommunicate — literally "to number among infidels." Researchers encountering this phrase in ecclesiastical sources should recognize it as a term of art for excommunication rather than a generic insult.
Black's 1st edition entry contains a notable artifact: the opening phrase references an "oath of office" and "grand jury," language that appears garbled or misattributed — likely a typesetting or compilation error. The 2nd edition corrects this, and Burrill's entry is the most complete and reliable of the three. Researchers relying on the 1st edition definition should treat that preamble with caution.
Because infidelis is a purely historical term with no modern statutory or common law life, it will appear almost exclusively in older treatises, Year Books, feudal land records, and ecclesiastical materials. It does not have a living doctrinal presence in any modern jurisdiction.
Historical Dictionary Support
All three source dictionaries agree on the two core meanings: the religious (infidel, heathen) and the feudal (one who violated fealty). Burrill's entry is the most substantive, providing the Latin breakdown, the canonical phrase inter infideles connumerare with attribution to Cowell, and the feudal usage with citations to Capitularies of Charlemagne and Spelman. Black's two editions are consistent with each other on substance, though the 1st edition contains the apparent corruption noted above.
What the historical dictionaries do not address: the practical legal consequences that attached to the status of infidelis in English courts — particularly the historical rule that an infidel could not take a Christian oath and therefore could not give competent testimony. That evidentiary dimension is documented in treatises on evidence and court practice rather than in these dictionary entries, and researchers interested in the legal disabilities of infideles in English proceedings should look beyond these sources.
Jurisdictional Note
Infidelis is a term of historical rather than jurisdictional variation. It operated across the feudal and ecclesiastical legal systems of medieval Europe, with English common law inheriting both usages. No modern jurisdiction uses the term as operative law.