Definition
De Prerogativa Regis (Latin: "concerning the prerogative of the king") refers to an English statute of 1324, enacted under Edward II (though historically attributed to Edward I), that codified certain prerogative rights of the Crown. The statute is principally known for two distinct grants of royal authority:
1. WARDSHIP OVER IDIOTS: The Crown was entitled to take wardship of the lands belonging to persons found to be idiots (those born without mental capacity), receiving the profits of those lands during the person's lifetime while providing for their necessaries and preserving the estate without waste.
2. WARDSHIP OVER LUNATICS: Distinct from idiots, lunatics (those who had once been of sound mind but lost their reason) were subject to a different Crown interest — the king was entitled to custody of their persons and estates, but only during periods of incapacity, with the obligation to restore the estate upon recovery.
These two categories — idiot and lunatic — created separate legal regimes under the statute, a distinction that persisted in English law for centuries and shaped the development of mental incapacity doctrine throughout the common law world.
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Common Confusion
The statute's two categories — idiot and lunatic — are frequently collapsed in later historical commentary, but De Prerogativa Regis treated them as legally distinct. An idiot was one born without understanding; a lunatic was one who had lost understanding after birth and might regain it. The Crown's interest in each case differed accordingly: profits of an idiot's land belonged to the Crown permanently (for the life of the idiot); profits of a lunatic's estate were held in trust and subject to restoration upon recovery. Conflating the two distorts the legal history of mental incapacity and guardianship.
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Why It Matters in Research
De Prerogativa Regis is a foundational document for several lines of historical legal research, and researchers approaching it from secondary sources face a number of traps.
ATTRIBUTION CONFUSION: The statute is conventionally cited as 17 Edw. II, but it has also been attributed to Edward I in older authorities, including Blackstone and Stephen. Black's Law Dictionary cites it as "17 Edw. I. St. 1, c. 9," which reflects this older attribution. The actual date and regnal attribution were disputed among legal historians, and researchers should not assume consistency across historical sources.
MENTAL INCAPACITY LAW: This statute is the root source for the distinction between idiocy and lunacy in English law — a distinction that drove separate procedural mechanisms (inquisitions of idiocy vs. inquisitions of lunacy) and separate equitable interventions by the Court of Chancery. Any research into the historical law of mental capacity, guardianship, or the parens patriae doctrine will encounter De Prerogativa Regis as a foundational reference.
PREROGATIVE DOCTRINE: The statute is relevant not only to mental incapacity but to the broader history of royal prerogative. It represents an early effort to codify, rather than merely assert, prerogative rights — which itself has significance for the constitutional history of the relationship between statute and prerogative.
WARDSHIP RESEARCH: Researchers tracing the history of wardship and feudal incidents will find De Prerogativa Regis cited alongside other Edwardian legislation. It should be distinguished from prerogative wardship arising from feudal tenure (wardship of infant heirs), which operated under different rules.
STEPHEN'S COMMENTARIES: Black's cites 2 Stephen's Commentaries at 529 as secondary authority. James Stephen's Commentaries on the Laws of England is a reliable secondary source for this material and remains available in the Law Mind corpus. Researchers should consult it alongside Blackstone's Commentaries (Book I) for the received common law understanding of this statute's operation.
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Historical Dictionary Support
Black's Law Dictionary provides a compact but accurate entry, identifying the statute's primary operation regarding idiots — Crown wardship, receipt of profits, duty to find necessaries, and prohibition on waste — and citing Stephen's Commentaries as authority. The entry is brief and omits the lunatic/idiot distinction that is central to the statute's doctrinal significance.
Older treatise literature, including Blackstone and Coke, gives substantially more treatment to De Prerogativa Regis than dictionary sources. Coke's commentary on the statute (in his work on Littleton and in his Institutes) is the most detailed early exposition and treats the idiot/lunatic distinction with precision. Blackstone's Commentaries synthesize the statute's operation within his broader treatment of royal prerogative. Neither Coke nor Blackstone appears in Black's entry, which limits the dictionary's usefulness as a standalone source for this term.
Historical sources are consistent on the core content — Crown wardship over mental incompetents — but vary in their characterization of the statute's constitutional significance. Later commentators writing after the development of Chancery jurisdiction over lunacy (consolidated under Lord Chancellor by the 17th century) sometimes treat De Prerogativa Regis as largely superseded in practice, while still acknowledging its doctrinal primacy as the source of Crown authority.
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Jurisdictional Note
De Prerogativa Regis is an English statute and its direct operation was confined to England and Wales. American jurisdictions did not receive the statute as part of the common law in the same formal sense, but the underlying doctrine — particularly the parens patriae power over those unable to care for themselves — was transplanted into American equity practice and eventually into statutory guardianship regimes. Researchers tracing the American law of mental incapacity should treat De Prerogativa Regis as doctrinal background rather than binding authority.
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Encyclopedia Cross-Reference
See Law Mind Encyclopedia — Royal Prerogative (for the statute's place in the history of codified prerogative rights); Wardship (for the feudal and prerogative wardship regimes); Idiots and Lunatics in Law (for the mental incapacity distinction and its procedural consequences); Parens Patriae (for the doctrine's development from the Crown's prerogative role).
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