Definition
In law, "letters" refers to formal written instruments issued by a court, government authority, or other recognized body that confer a specific power, right, or status upon the named recipient. Unlike ordinary correspondence, legal letters are operative documents — their issuance itself creates or authorizes something. The term almost never appears alone in legal usage; it functions as the first word of a compound term identifying a particular grant of authority.
The most frequently encountered forms in legal research include:
1. Letters Testamentary — Issued by a probate court to the executor named in a will, authorizing that person to administer the decedent's estate.
2. Letters of Administration — Issued by a probate court when a person dies intestate (without a will), or when no valid executor is available, appointing an administrator to manage and distribute the estate's personal property.
3. Letters Patent — A formal government instrument granting an exclusive right, privilege, or title to an individual — historically including land grants, noble titles, and monopolies; in modern usage most commonly associated with patents for inventions.
4. Letters Rogatory — A formal request from a court in one jurisdiction to a court in another (often a foreign country) to perform a judicial act, such as taking testimony or serving process.
5. Letters of Marque — A historical government instrument authorizing a private vessel to seize enemy ships during wartime. Largely obsolete in modern law.
6. Letters of Credit — A financial instrument issued by a bank or other institution guaranteeing payment to a beneficiary upon fulfillment of specified conditions. Governed in U.S. commercial law by Article 5 of the Uniform Commercial Code.
Common Language
Modern common usage (Wiktionary): Plural of "letter" — written or printed communications addressed to a person or organization.
Historical common usage (Webster's 1913): "A written or printed communication; a message in writing." Also used in the plural to mean learning or literature broadly ("a man of letters").
The gap between common and legal usage is significant. In everyday English, letters are communications — they convey information from sender to recipient. In law, letters are instruments — documents that themselves confer authority, create legal status, or establish a right. A letter of administration does not merely inform the administrator of something; it is the legal source of their power to act. Researchers unfamiliar with this distinction may misread historical legal documents or misclassify legal letters as mere correspondence in archival searches.
Recognized Forms
/SUBTYPES
The compound forms of "letters" constitute the operative legal vocabulary. The principal subtypes recognized in the Law Mind corpus include: Letters Testamentary, Letters of Administration (and the variant Letters of Administration with the Will Annexed, issued when a will exists but no executor can serve), Letters Patent, Letters Rogatory, Letters of Marque, and Letters of Credit. Each subtype has its own doctrinal history, procedural requirements, and research trail.
Why It Matters in Research
The word "letters" in a historical legal document is a near-certain signal that you are reading an instrument of authority, not correspondence. Misidentifying the document type can send research in the wrong direction.
In probate research, the distinction between letters testamentary and letters of administration is foundational. Letters testamentary derive their force from the will; letters of administration derive their force entirely from the court's appointment. Historical records — particularly in colonial and early American probate — sometimes use these terms loosely or interchangeably, especially in informal county court records. Cross-check the underlying document against the presence or absence of a will in the probate file.
The letters of credit subtype sits in a completely different doctrinal universe from the probate letters. Researchers moving between commercial law and estate law should treat these as effectively separate terms that happen to share a first word.
Letters rogatory appear in international litigation materials and treaty-based judicial assistance frameworks. The modern procedural vehicle in U.S. federal courts is governed by statute (28 U.S.C. § 1781), but older federal and state court records will use the traditional term. Frequency of appearance increases sharply in maritime, admiralty, and international commercial cases.
Letters of marque are constitutionally referenced (Article I, Section 8 of the U.S. Constitution grants Congress the power to grant them), making the term relevant to constitutional history research even though the instrument is practically extinct.
Historical Dictionary Support
Bouvier's Law Dictionary focuses its treatment of "letters" almost entirely on letters of administration in the probate context, providing a functional description of the instrument's scope: the grant of "full power to administer the goods, chattels, rights, and credits" of the deceased, including authority "to ask, collect, levy, recover, and receive" outstanding credits. This reflects the dominant practical usage of the term in nineteenth-century American legal practice, where letters of administration were among the most commonly issued court instruments.
Rapalje & Lawrence's entry does not provide substantive text in the available excerpt, but the term's presence in both major nineteenth-century dictionaries confirms it was standard vocabulary requiring definition for practitioners of that era.
Both historical sources reflect a predominantly probate-oriented understanding of "letters" as a legal term of art. Neither adequately covers letters of credit as a distinct commercial instrument — unsurprising, given that Article 5 UCC standardization is a twentieth-century development — or letters rogatory as they function in modern international judicial assistance practice. Researchers relying solely on historical dictionaries for the letters of credit subtype should consult commercial law sources directly.
Jurisdictional Note
Probate letters (testamentary and of administration) are issued under state court authority; requirements, forms, and terminology vary by state. Some jurisdictions issue a single document covering both real and personal property; others historically limited letters of administration to personal estate, requiring separate proceedings for real property. Federal courts do not issue probate letters.
Encyclopedia Cross-Reference
Contracts — Preliminary Negotiations, Letters of Intent, and Memoranda of Understanding (The Law Mind Contracts & Commercial Law Encyclopedia)
IRS Notice of Deficiency 90-Day Letter (The Law Mind Tax Encyclopedia)