Definition
Decretales Bonifacii Octavi (Latin: "Decretals of Boniface the Eighth") is the formal name for a supplemental collection of canon law issued by Pope Boniface VIII in 1298. The collection is far more commonly known by its popular title, the Liber Sextus Decretalium — the "Sixth Book of the Decretals" — or simply the Sextus or Sexte.
The compilation served as an official addition to the five books of the Decretales Gregorii Noni (the Decretals of Gregory IX, issued in 1234). By appending his collection as a sixth book, Boniface VIII gave the work its enduring popular name. The Liber Sextus gathered papal constitutions, conciliar canons, and authoritative rulings accumulated in the decades following the Gregorian compilation, organizing them into the same five-part structure (books, titles, chapters) that governed the earlier Decretals. It became a foundational text of the Corpus Iuris Canonici, the body of canon law that governed the Western Church for centuries and that continues to inform historical ecclesiastical legal analysis.
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Why It Matters in Research
Researchers encountering Decretales Bonifacii Octavi in historical legal sources should recognize immediately that the term is almost never used in running text. Primary sources — glosses, commentaries, court records, and treatises from the medieval and early modern periods — virtually always cite this collection as the Liber Sextus, Sextus Decretalium, or simply Sexte. A researcher who searches only for the formal papal title will miss the overwhelming majority of citations and commentary.
The Liber Sextus was a living legal instrument: it carried the glossa ordinaria composed by Johannes Andreae (d. 1348), making it inseparable from that apparatus in most manuscript and printed editions. Citations in historical sources that appear to be to the Sextus are often, in practice, citations to Johannes Andreae's commentary rather than the text itself. Researchers working with pre-Tridentine ecclesiastical records, church court proceedings, or canon law treatises need to understand this layered citation practice.
Within the Law Mind corpus, this term connects directly to the broader architecture of the Corpus Iuris Canonici. Researchers tracing the canon law sources cited in English ecclesiastical courts, prerogative court proceedings (including testamentary and matrimonial causes), or the mixed civil-canon law tradition of the admiralty and civilian courts will encounter the Sextus regularly. English civilians trained at Doctors' Commons relied on the Corpus Iuris Canonici, including the Liber Sextus, as authoritative reference material well into the early modern period, even after the Henrician break with Rome limited its formal ecclesiastical authority in England.
The 1298 date is a useful anchor: any legal source citing the Sextus is drawing on post-1234, post-Gregorian canon law, placing it in the mature scholastic canonical tradition rather than the earlier Decretum of Gratian.
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Historical Dictionary Support
Both Burrill and Black agree on the essentials: this is a canon law collection issued by Boniface VIII in 1298, more commonly known as the Liber Sextus Decretalium. Burrill's entry is purely a cross-reference, directing the reader to the Sextus Decretalium entry rather than elaborating here. Black's adds the date and the explicit framing as a "supplemental collection," which is accurate — it was designed to follow and complement the Gregorian Decretals rather than replace them.
Neither source addresses the gloss apparatus, the collection's place within the full Corpus Iuris Canonici, or its practical use in English civilian and ecclesiastical courts. Neither source notes that editions of the Liber Sextus were printed continuously from the late fifteenth century onward and that the text researchers are likely to encounter in early printed books is the edition with Johannes Andreae's gloss, not a bare canonical text. This is a meaningful gap for any researcher working with physical or digitized historical legal volumes.
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Jurisdictional Note
The Liber Sextus formally governed the universal Western Church and was authoritative throughout Catholic Europe. In England, its operative authority in ecclesiastical courts was curtailed but not eliminated by the Reformation-era statutes of the 1530s; English civilian and church court practice continued to reference it in relevant proceedings, particularly matrimonial and testamentary causes, through the seventeenth century and into the eighteenth where no English statutory rule displaced the canonical rule.
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Encyclopedia Cross-Reference
See Law Mind Encyclopedia: Corpus Iuris Canonici; Canon Law in English Courts; Liber Sextus Decretalium
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