Definition
Insimul computassent (Latin: "they accounted together") is a common law pleading term designating a specific count in an action of assumpsit. The count alleged that the plaintiff and defendant had settled and stated their mutual accounts, and that the defendant had thereby promised to pay the plaintiff the balance found due. It was not a claim arising from an original debt or underlying transaction, but rather from the parties' agreement upon a final balance — the stated account itself serving as the foundation of the action.
Common Confusion
Insimul computassent should not be confused with the common law action of account (also called account render or de computo). Account render was a distinct and earlier form of action requiring a defendant to render an accounting before an auditor appointed by the court; it was cumbersome, slow, and largely superseded by assumpsit. Insimul computassent, by contrast, presupposed that the accounting had already occurred — the parties had already settled — and the action was simply to enforce the resulting promise to pay. A researcher finding references to "action of account" in early sources is not looking at the same procedural animal.
Why It Matters in Research
This term belongs to the technical vocabulary of common law pleading and appears almost exclusively in sources predating the procedural reforms of the nineteenth century. Researchers encounter it most often in English and early American case reports involving merchants, tradesmen, and others whose dealings required periodic account settlements.
The critical navigational point is that insimul computassent is a count within assumpsit, not a standalone form of action. A researcher reading a historical pleading record or case report that mentions it should understand the broader assumpsit framework: the count was one of several that might appear together in a declaration, alongside counts for money had and received, money lent, or goods sold and delivered. Finding the term in a pleading does not necessarily mean the account-stated theory was the one that ultimately prevailed.
The count was procedurally significant because an account stated was treated as a new promise, distinct from the original dealings. This meant the statute of limitations ran from the date of the stated account, not from the underlying transactions — a distinction that mattered enormously in practice and that researchers should watch for when limitations questions arise in historical litigation.
After the Field Code reforms spread across American jurisdictions from the mid-nineteenth century onward, code pleading replaced the common law system of special counts. Insimul computassent as a formal pleading label disappears from American practice at that point. The substantive doctrine of account stated survived the procedural reforms and remains operative today, but the Latin count name does not appear in modern pleadings. Researchers working across the reform boundary should not expect to find the term in post-code materials; instead, look for "account stated" as the continuing doctrinal label.
Historical Dictionary Support
Black's Law Dictionary gives a concise and accurate account: the term means "accounted together," identifies it as the name of the count in assumpsit upon an account stated, and captures the essential averment — that the parties had settled their accounts and the defendant had promised to pay the balance. This entry is reliable as far as it goes.
What Black's does not elaborate is the procedural texture around the count: how it interacted with other counts in the same declaration, how courts treated the requirement of mutual settlement (as opposed to a unilateral statement), or how the count's elements were tested on demurrer. For those dimensions, researchers need to look beyond dictionary sources to treatises on common law pleading — Chitty's Pleading and Stephen's Principles of Pleading being the standard authorities for the English tradition, and their American counterparts for early U.S. practice.
Jurisdictional Note
The count was a feature of English common law procedure and was adopted in American jurisdictions following English practice. Its useful life in American courts ended jurisdiction by jurisdiction as code pleading was adopted, beginning with New York in 1848 and spreading through most states by the late nineteenth century. The underlying doctrine of account stated persists across American jurisdictions today, though its elements and limitations treatment vary by state.