Definition
A Latin phrase meaning "after the Conquest," referring specifically to the Norman Conquest of England in 1066. The phrase was used as a dating and distinguishing element in the formal titles of English kings, particularly to differentiate monarchs who bore the same name but reigned in different eras — those before the Conquest and those after it.
The phrase carries its most precise legal and historical significance in royal titulature: when Edward I began inserting the phrase into the royal style, and later when Edward III adopted it consistently, the purpose was to clarify numbering. Edward I through Edward III all reigned after the Conquest, but there had been Anglo-Saxon kings named Edward before 1066 — Edward the Elder, Edward the Martyr, Edward the Confessor. The phrase "post conquestum" anchored the numbering of these post-Conquest Edwards to a fixed historical point, distinguishing them from their pre-Conquest namesakes.
Common Confusion
There is a conflict in the historical sources on exactly when the phrase was first introduced into royal titles. Black's Law Dictionary (both editions), Bouvier, and Rapalje & Lawrence attribute the insertion to Edward I, while Burrill credits Edward III (reigning 1327–1377) as the first to actually use it, citing Cowell and Blount. This is not a trivial discrepancy. Edward I may have used a version of the phrase informally or in limited instruments, but the consistent and recognized adoption in royal style appears to date from Edward III's reign — a period when the numbering issue became more pressing given that three consecutive kings bore the name Edward. Researchers relying solely on Black's or Bouvier without consulting Burrill may carry away an imprecise attribution.
Why It Matters in Research
This term appears almost exclusively in historical legal materials and is unlikely to surface in modern statutes, cases, or legal instruments. Its significance for researchers is contextual and interpretive rather than doctrinal.
When working with medieval English legal texts, royal charters, writs, or chronicles from the thirteenth and fourteenth centuries, encountering "post conquestum" in a royal title or dating clause signals that the document is locating itself chronologically within the post-1066 lineage of English kingship. Understanding the phrase prevents misreading of dating conventions in primary sources from this period.
For researchers using Bracton's De Legibus et Consuetudinibus Angliae — the foundational English common law treatise — Burrill specifically cites Bracton's folio 7 in connection with post conquestum, suggesting the phrase or its conceptual framework appears in that text. Researchers working in Bracton's treatise should be alert to this usage as part of the broader royal and feudal legal framework Bracton articulates.
The phrase is also an entry point into questions of English succession law and feudal title, since the Conquest itself was the legal watershed event establishing the basis of Norman land tenure in England. The distinction between pre- and post-Conquest periods permeates medieval English property and inheritance doctrine.
Historical Dictionary Support
All five source dictionaries agree on the core meaning — the phrase denotes "after the Conquest" and functioned as a titular marker for post-1066 English kings. The agreement ends with attribution.
Black's Law Dictionary, Black's 2nd Edition, Bouvier, and Rapalje & Lawrence all trace the phrase to Edward I (reigned 1272–1307), citing Tomlins as the authority. Burrill diverges, citing Cowell and Blount to place formal adoption with Edward III in 1328. Burrill also adds the explanatory rationale — the need to distinguish same-named kings across the Conquest divide — which is more informative than any of the other entries. Burrill further supplies the Bracton citation, grounding the phrase in the primary legal literature of the period rather than relying solely on secondary lexicographers.
None of the historical sources explore the phrase's connection to feudal land tenure doctrine or the broader legal significance of the Conquest as a constitutional dividing line in English legal history. Researchers should treat these dictionary entries as signposts to the primary sources (Bracton, Cowell, Blount, Tomlins) rather than comprehensive treatments.
Jurisdictional Note
This phrase is specific to medieval English legal history and royal titulature. It has no recognized usage in modern common law jurisdictions and carries no operative legal meaning in contemporary practice anywhere in the common law world.