Definition
"A mortgage" (as a fixed phrase, not the general instrument) is a principle of equity holding that an instrument intended from its inception to operate solely as a mortgage cannot be converted by any internal clause, covenant, or stipulation into an outright purchase or conveyance — regardless of what future event that clause purports to trigger. Once a transaction is characterized as a mortgage at its creation, it remains a mortgage in law and in equity.
The phrase captures one of the foundational equitable doctrines governing secured lending: the parties cannot, at the time of executing the mortgage instrument itself, contract away the mortgagor's right to redeem. Any provision within the deed that would automatically transform the mortgage into an absolute conveyance upon default, lapse of time, or other specified condition is void as an attempt to "clog the equity of redemption."
This is distinct from a later, independent agreement between the parties — made after the mortgage is already in place, at arm's length, and without oppression — which may in some circumstances validly transfer the mortgagor's interest to the mortgagee.
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Common Confusion
"A mortgage" as a legal phrase of art is easily overlooked because it reads as a generic article-plus-noun rather than a term of art. Researchers encountering the phrase in older equity decisions or treatises may miss that it signals this specific principle rather than a general reference to a mortgage instrument. It is not the same as saying "once a mortgage, always a mortgage," which is the broader equitable maxim — though the two are closely related and often discussed together. The broader maxim addresses all attempts to clog or extinguish the equity of redemption; "a mortgage" (as used in Rapalje & Lawrence) focuses specifically on the drafting of the original instrument and the impossibility of building a purchase mechanism into the mortgage deed itself.
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Why It Matters in Research
Researchers working in 19th-century equity materials — particularly in mortgage foreclosure, redemption, and clogging-of-equity cases — will encounter this phrase used as a shorthand signal that the court is applying the principle that the instrument's character is fixed at execution. Several research traps exist:
First, the phrase appears without quotation marks or special formatting in older reports, making it easy to read past as throat-clearing rather than as invocation of doctrine.
Second, the underlying principle has eroded in some modern American jurisdictions through statute and commercial practice, particularly in the context of deeds of trust and certain commercial mortgage structures. A researcher relying on 19th-century equity holdings without checking subsequent legislative or judicial modification may find the doctrine significantly qualified or displaced.
Third, the doctrine operates at the intersection of mortgage law and the equity of redemption — meaning corpus connections run in multiple directions. Cases discussing "clogging," "once a mortgage always a mortgage," and "collateral advantage" doctrine are all relevant, and the researcher should pursue all three threads before concluding on the state of the law in any given jurisdiction or period.
Fourth, in English equity materials (which fed directly into American practice through Story, Washburn, and other treatise writers), the principle is robustly developed. American courts received it but applied it with varying strictness, particularly as commercial real estate lending became more sophisticated in the late 19th and 20th centuries.
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Historical Dictionary Support
Rapalje & Lawrence state the principle concisely: an indenture "intended in the first instance to operate as a deed of mortgage only, and not as a purchase deed, cannot by any clause or agreement therein be made to operate as a purchase or otherwise than as a mortgage upon any specified event," citing Brown. The formulation is precise and useful. It captures two elements that later commentary sometimes separates: (1) the intent-at-inception test, and (2) the inefficacy of in-instrument conversion clauses regardless of what triggering event is specified.
What the Rapalje & Lawrence entry does not address is the boundary question — when a subsequent, separate agreement suffices to convert or extinguish the mortgagor's interest. That gap is significant for research, because the cases turn heavily on whether a later transaction is genuinely independent or is merely a continuation of the original mortgage arrangement in disguise. Researchers should not treat the dictionary entry as a complete statement of the doctrine; it establishes the core rule but leaves the harder questions to treatise and case law.
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Jurisdictional Note
The principle is rooted in English equity and was widely adopted in American courts of equity throughout the 19th century. Modern application varies: some states have substantially codified mortgage law in ways that displace or modify the common-law equity doctrine, and commercial mortgage practice frequently involves structures — including deed-of-trust arrangements and intercreditor agreements — that test the doctrine's limits. Researchers should verify current statutory treatment in the relevant jurisdiction before applying historical equity authorities.
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Encyclopedia Cross-Reference
The Law Mind Property Law Encyclopedia:
— Mortgages: Priority of Mortgages and Subordination Agreements (property_60) — relevant to understanding how mortgage character affects priority disputes
— Mortgages: Mortgage Fraud (property_67) — relevant where conversion-of-instrument arguments arise in fraud contexts
— Mortgages: Reverse Mortgages (HECM) (property_68) — contrast with modern statutory mortgage forms where redemption rights are structurally modified
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