Definition
A Latin term from medieval law meaning to pledge or mortgage lands. The term describes the act of giving land as security for a debt or obligation — the transferring of a possessory or encumbrance interest in real property to a creditor until the underlying obligation is satisfied. The related noun form, invadiatio, denotes the pledge or mortgage itself, as distinct from the act of creating it.
Common Confusion
INVADIARE should not be confused with a present conveyance of land. The act of invading land in the medieval sense was a security transaction: the grantor retained an equity of redemption or right to reclaim the property upon satisfying the debt. This is functionally analogous to what modern law calls a mortgage, but in early common law the mechanics and consequences of default differed substantially from modern mortgage doctrine. Researchers should not read modern foreclosure concepts backward into sources using this term.
Why It Matters in Research
INVADIARE is a term that appears almost exclusively in medieval and early common law sources — Year Books, Latin legal instruments, and early treatises — and is essentially absent from modern practice. Its research value is therefore primarily as a key to reading historical documents rather than as a live legal concept.
Several traps await the researcher working with historical sources:
First, the line between invadiare (pledge of land) and other early security arrangements — including gage, vivum vadium (living pledge), and mortuum vadium (dead pledge, the direct ancestor of "mortgage") — is not always cleanly maintained in historical texts. Scribes and compilers sometimes used the terms interchangeably. When a source uses invadiare, it is worth examining the surrounding language to determine whether a living gage or dead gage arrangement is contemplated, as the economic consequences differed: under a living gage, rents and profits from the land applied toward the debt; under a dead gage, they did not.
Second, the term invadiatio (the noun companion to the verb) appears in Latin instruments where an English summary might simply say "mortgage." Researchers translating or abstracting early deeds should treat the two forms as related but distinct: the verb describes the transaction, the noun describes the instrument or status created by it.
Third, the term has no footprint in American case law or statutory materials. Researchers encountering it in American legal dictionaries — including Bouvier and Black — are seeing it preserved as historical vocabulary imported from English legal Latin, not as operative American doctrine. It is a bridge term for understanding sources, not a term that carries its own doctrinal weight in American courts.
Historical Dictionary Support
The four historical sources are in close agreement on the core meaning, which is unusually tidy for a Latin legal term. Black's (1st and 2nd editions) and Rapalje & Lawrence all converge on "to pledge or mortgage lands." Bouvier renders it as "to mortgage lands" and adds the useful companion entry for invadiatio as "a pledge or mortgage," sourcing it to Tomlin's Law Dictionary — a reminder that Bouvier was drawing on an English lexicographic tradition that treated these Latin survivals as worthy of preservation even as they faded from practice.
What the historical sources do not do is distinguish invadiare from the more specific categories of early security interests in land. None of the four entries engages the vivum vadium / mortuum vadium distinction, nor do they situate the term within the broader history of the mortgage's development in equity. For that context, researchers will need to consult historical treatises on real property rather than the dictionary shelf.
Jurisdictional Note
INVADIARE has no active jurisdictional footprint. As a term of medieval Latin law, it is relevant primarily to English legal history and to the interpretation of pre-modern instruments in jurisdictions with common law roots. American and English courts do not apply it as operative doctrine.