Definition
In Scots law, the heir of line is the person who succeeds to a deceased's heritable property — principally land and other heritable rights — by right of blood through lineal descent. The heir of line takes the heritage of a predecessor by operation of the general rules of succession, as distinguished from heirs who take under particular legal appointments or by special designation.
Historically, Scots law divided a deceased person's succession into two broad streams: moveable estate (personal property) and heritable estate (land and rights attached to land). The heir of line was the person entitled to the heritable stream — the one who stood next in the line of blood descent to the deceased. This was typically the eldest son under the preference for primogeniture, and in default of male heirs, the eldest daughter or, in some circumstances, the heir-portioner sharing with sisters.
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Common Confusion
HEIR OF LINE should not be confused with HEIR AT LAW (the common law equivalent in English and American systems) or with HEIR OF PROVISION (a Scots law term for one named heir under a special deed or settlement, as opposed to one taking by general operation of law). Nor should it be confused with HEIR OF TAILZIE, the Scots term for one succeeding under an entail. The distinctions matter in historical research because the same decedent's estate in Scotland could produce different heirs depending on which category of property and which species of heirship applied.
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Why It Matters in Research
This term is almost exclusively a term of Scots law and will appear in sources dealing with Scottish heritable succession, Scottish feudal property history, and pre-1964 Scottish estate administration. Researchers working in the Law Mind corpus should be alert to several navigational points.
First, the term's relevance diminished sharply after the Succession (Scotland) Act 1964, which abolished the separate rules for heritable and moveable succession and replaced the heir of line concept with a unified scheme of intestate succession. Sources predating 1964 will use the term in its full technical sense; sources postdating 1964 may reference it only in historical or comparative discussion.
Second, the heir of line concept connects directly to escheat doctrine. Because the heir of line was the person who took in default of testamentary provision, the absence of an heir of line — a total failure of the blood line — was the trigger for the property to fall to the Crown by ultimus haeres (the Crown as last heir). Researchers tracing escheat questions in Scottish estates should follow the heir of line analysis before reaching the escheat question.
Third, the term appears in feudal tenure materials and old conveyancing records. Scottish writs and sasines frequently use "heirs whomsoever" or "heirs of line" as words of limitation defining who could succeed to a feudal grant. These phrases carry precise heritable property implications that differ from superficially similar English conveyancing language.
Fourth, researchers should be cautious about conflating Scots sources with Irish or English sources that use "heir of the blood" or "heir in tail" language. The institutional frameworks are distinct.
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Historical Dictionary Support
Black's Law Dictionary defines the term concisely: the heir of line is one who "succeeds lineally by right of blood" and who "succeeds to the deceased in his heritage, i.e., lands and other heritable rights derived to him by succession as heir to his predecessor," citing Forbes's Institutes. This definition is accurate as far as it goes but is skeletal. It does not address the relationship between heir of line and the competing categories of Scots heirs (heir of provision, heir of tailzie, heir in mobilibus), nor the pre-1964 bifurcation of heritable and moveable succession that gives the term its structural importance.
General English-language legal dictionaries outside the Scots law tradition largely omit this term or treat it as a curiosity. Researchers relying solely on American or English sources will find little support. The authoritative institutional treatment remains in the Scottish institutional writers — Forbes, Stair, Erskine, and Bell — whose works provide the framework Black's is summarizing. Researchers needing depth should go to those primary Scottish institutional sources rather than expecting further elaboration from Black's alone.
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Jurisdictional Note
This term is specific to Scots law. It has no direct counterpart in English common law or in American law, though functional analogies exist (heir at law, heir of the body). Modern Scottish succession law, as reformed by the Succession (Scotland) Act 1964, renders the term largely obsolete for contemporary practice but essential for historical estate research involving Scottish heritable property.
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Encyclopedia Cross-Reference
Escheat — When Property Passes to the State for Lack of Heirs (The Law Mind Trusts, Estates & Probate Encyclopedia): The failure of an heir of line in Scots law was the precondition for the Crown's claim as ultimus haeres; this entry provides the broader context for what happens when the line of descent is exhausted.
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