Definition
A writ of old English law authorizing the seizure of goods belonging to foreign merchants found within England, issued as a remedy when a foreign state had wrongfully taken the goods of an English subject (denizen) abroad and refused to make restitution. The name translates roughly as "arrest made upon the goods of alien merchants." The writ operated as a state-sanctioned reprisal: if a foreign sovereign denied justice to an English merchant, the Crown could authorize seizure of that foreign nation's merchants' property in England as a form of coercive recompense.
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Common Confusion
This writ is closely related to — and in civilian legal tradition is synonymous with — the concept of reprisals (reprisalia). Historical writers also used the term clarigatio, borrowed from ancient civilian practice, to describe the same or closely analogous remedy. Researchers encountering any of these three terms in medieval or early modern sources are likely looking at the same underlying mechanism. The distinction, where one exists, is largely terminological rather than substantive: clarigatio emphasized the formal demand for satisfaction before seizure; reprisalia described the retaliatory act itself; the writ of arresto facto super bonis mercatorum alienigenorum was the specific English procedural instrument through which the reprisal was executed.
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Why It Matters in Research
This term belongs to a narrow but important body of medieval and early modern commercial law governing relations between English merchants and foreign states. Several research traps are worth noting.
First, the writ is effectively obsolete and appears almost exclusively in historical sources. Modern researchers will encounter it in treatises and registers from the thirteenth through seventeenth centuries, not in contemporary practice. Its presence in Black's 2nd Edition Supplemental reflects its significance as a historical anchor for doctrines that evolved into modern concepts of state responsibility and diplomatic protection of nationals abroad.
Second, the Registrum Omnium Brevium (Reg. Orig.) is the primary procedural source cited for this writ. Researchers working with Reg. Orig. 129 should note that different editions and manuscript versions of the Registrum vary in their numbering, and the relevant passage may require cross-referencing against other early registers.
Third, the writ sits at the intersection of several doctrinal histories: the law of reprisals in international law, the English law of alien status (the distinction between denizen and alien), and the history of merchant law (lex mercatoria). Researchers tracing any of these threads may encounter this writ as a waypoint even when it is not their primary subject.
Fourth, the term alienigenorum — referring to persons born under the allegiance of a foreign sovereign — has its own doctrinal freight. Distinguishing aliens from denizens was central to the writ's operation, and the categories did not map cleanly onto later citizenship concepts. Sources that use alien loosely may obscure whether the writ would have applied.
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Historical Dictionary Support
Black's Law Dictionary (2nd Ed., Supplemental) provides the only entry among the Law Mind shelf sources. The entry is brief but accurate in substance: it correctly identifies the writ as operating upon denial of restitution by a foreign state, correctly cites Reg. Orig. 129, and correctly notes the civilian terminology clarigatio and the modern civilian term reprisalia as equivalents.
What Black's does not capture is the procedural complexity behind the writ's issuance. The writ was not self-executing — it required a showing that restitution had been sought and denied, and it was issued under royal authority rather than as an ordinary common law remedy. This royal and diplomatic dimension connects the writ to the law of nations as understood in early modern England, a context that Black's entry elides entirely.
No other Law Mind shelf dictionaries include this term, which is consistent with its status as a specialized historical writ rather than a term of ongoing legal currency.
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Jurisdictional Note
This is an English writ with no direct counterpart in American law. The underlying concept of state reprisal against alien property in response to foreign denials of justice influenced early international law doctrine but was not received into American domestic legal procedure. Researchers working in American legal history will encounter the concept only in the context of the law of nations and early treatises on international commercial relations.
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