Definition
A Latin term from medieval English law meaning to forswear, abjure, or renounce something by oath. The act of forisjurare involved a formal sworn renunciation — of a country, a realm, a parental relationship, or some other legal status — with defined legal consequences following from the oath. Two recognized applications appear consistently in the historical sources:
1. Provinciam forisjurare: To forswear the county or country — to swear a solemn oath that one will not return. When applied to the kingdom as a whole, this was the practice later known as abjuration of the realm.
2. Forisjurare parentilam: To remove oneself from parental authority by oath. The person who performed this act forfeited heritable rights — losing standing as an heir under the law then in effect.
Why It Matters in Research
This term belongs to the stratum of Latin legal vocabulary that was current in medieval English legal practice and appears in Bracton, Spelman, and the Laws of Edward the Confessor, but had largely disappeared from active use by the early modern period. Researchers encountering forisjurare in historical legal records should treat it as a technical term of medieval procedure, not a general synonym for renunciation or oath-taking.
The critical research trap is treating forisjurare and abjuration as fully interchangeable. Burrill draws the connection explicitly but notes that abjuration of the realm was the later, more developed form. Forisjurare in its earlier uses was the broader act; abjuration came to refer specifically to the kingdom-wide renunciation with its elaborate procedural requirements. A document using forisjurare may predate the procedural formalities associated with abjuration proper, and the two terms should not be assumed to describe identical processes.
Forisjurare parentilam is the more obscure application and represents an early form of legal emancipation from family authority — a concept with loose analogies in Roman law but distinct in English medieval practice. The consequence (loss of heirship) is what makes it legally operative, not the oath alone. Researchers working on inheritance disputes, medieval family law, or the history of emancipation doctrines should note this connection.
The term appears in sources that are themselves historical rather than practitioner texts — Bracton, Spelman, Du Cange, and the Laws of Edward the Confessor — which signals that even Black's Law Dictionary was treating this as a term of historical record rather than living practice.
Historical Dictionary Support
The historical dictionaries converge on the core meaning: to forswear by oath, to abjure, to abandon. All four sources agree that forisjurare encompasses sworn renunciation of a place or status. The variation lies in emphasis and coverage.
Burrill provides the most analytical treatment, tracing the term to foris (out) and jurare (to swear), and quoting directly from the Laws of Edward the Confessor (c. 6) for the provinciam forisjurare usage. Burrill also makes the explicit connection to abjuration of the realm as the later developed form, which is the most useful navigational note in the historical record. His entry is incomplete as reproduced — it breaks off mid-sentence — but the substance is the fullest among the sources.
Black's (both editions) preserves the two sub-forms — provinciam forisjurare and forisjurare parentilam — with attribution to Spelman and Du Cange respectively. The parentilam entry is notable for recording the legal consequence (loss of heritable rights), not merely the act, which is what gives it substantive legal content rather than mere ceremonial significance.
Rapalje & Lawrence is the most compressed, treating the term as essentially equivalent to abjuration and cross-referencing that entry without adding independent analysis.
None of the historical dictionaries situate forisjurare within a broader account of medieval procedure or explain how the sworn renunciation was formally executed or recorded. Researchers needing that context must go to Bracton, Crabb's History of English Law, or primary chronicle sources.