Definition
De aestimato (also rendered *de aestimato*) is a Roman law contract classified among the innominate contracts — agreements that did not fit neatly into the named categories of Roman law (sale, hire, loan, mandate) but were nonetheless enforceable once one party had performed. In de aestimato, the owner of property (land or goods) delivered it to another person at a fixed, agreed-upon valuation (*aestimatio*), with the recipient undertaking to either sell the property and remit the agreed price, or return the property itself. A third party could also serve as guarantor of that fixed price, bearing personal liability if the transaction was not completed as agreed.
The practical function of the contract resembled a consignment arrangement: the recipient gained possession and the opportunity to profit from a sale above the fixed price, while the owner was assured of receiving at minimum the stated valuation. If the goods sold for more, the surplus belonged to the recipient. If the goods could not be sold, return of the property discharged the obligation.
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Why It Matters in Research
De aestimato appears rarely in American and English common law sources because it is a creature of Roman civil law with no direct common law equivalent. Researchers encountering the term are most likely working in one of three contexts: (1) civil law jurisdictions or mixed jurisdictions (Louisiana, Quebec, South Africa) where Roman law concepts retained operative force; (2) treatises and digests on Roman law that informed equity jurisprudence; or (3) comparative law scholarship examining the roots of consignment, agency, and sale-or-return transactions.
The fragment preserved in Rapalje & Lawrence pairs the term with an unrelated note about promissory notes and sixty-day periods — an artifact of the source's original pagination. Researchers should disregard that pairing; the two entries are editorially adjacent, not conceptually linked.
The deeper research trap is conflating de aestimato with outright sale (*emptio venditio*) or with mandate (*mandatum*). The distinguishing feature is the fixed valuation held by a third-party guarantor, which gave the arrangement a tripartite structure absent in ordinary consignment. Equity courts in early American and English practice occasionally drew on innominate contract doctrine to resolve disputes that fell outside recognized common law forms, so awareness of de aestimato can help researchers contextualize arguments made in chancery proceedings before modern contract law consolidated these categories.
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Historical Dictionary Support
Rapalje & Lawrence provide the only entry among the Law Mind shelf sources. Their definition is brief but accurate in substance: they correctly identify de aestimato as an innominate contract involving a sale at a fixed price guaranteed by a third party. The entry reflects the standard treatment found in civil law digests of the nineteenth century, which generally followed Justinian's Institutes and the Digest (D. 19.3) in classifying the innominate contracts under the formula *do ut des*, *do ut facias*, *facio ut des*, *facio ut facias*. De aestimato fell within the *do ut facias* category — I give (the goods) so that you will do (sell them or return them).
What Rapalje & Lawrence do not provide is any discussion of how de aestimato was treated in equity or how it might map onto common law concepts of bailment, agency, or sale on approval. Nineteenth-century American legal dictionaries generally handled Roman law terms as reference items for civilians and scholars rather than as operative doctrine, and this entry is no exception. Researchers seeking fuller treatment should consult civil law commentators such as Pothier or the institutional writers of Scots law, who engaged more directly with the innominate contracts as living doctrine.
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Jurisdictional Note
De aestimato has no recognized doctrinal role in American common law jurisdictions. In Louisiana and other civil law or mixed-law jurisdictions, Roman-derived contract categories retained greater influence, and the concept's functional equivalent — the consignment or *vente à réméré*-adjacent arrangements — may appear under civilian terminology. Researchers working in common law contexts will encounter the term only in historical, comparative, or academic materials.
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