Assumpsit ("he has undertaken", from Latin, assumere), or more fully, action in assumpsit, was a form of action at common law used to enforce what are now called obligations arising in tort and contract; and in some common law jurisdictions, unjust enrichment. The origins of the action can be traced to the 14th century, when litigants seeking justice in the royal courts turned from the writs of covenant and debt to the trespass on the case. History Fragmentation of actions for breach of agreement In the early days of the English common law, agreements were enforced in local courts. Where one wished to enforce an agreement in the royal courts, it was necessary to fit one's claim within a form of action. In the 13th and 14th centuries the forms of action for the enforcement of agreements were covenant, debt, detinue, and account.<ref>See generally, Sir John Baker, An Introduction to English Legal Historically (4th ed, 2004); Professor David Ibbetson, Historical Introduction to the Law of Obligations (2nd ed).</ref> These were all writs in the praecipe form, meaning that they commanded the defendant to perform an act: for example, to keep a promise; to yield up a sum of money or chattel unjustly withheld; or to render accounts. These actions were subject to various limitations. For example, by the middle of the 14th century at the latest, it was necessary for a plaintiff in an action of covenant to have a deed. In an action of debt sur contract, a deed was not necessary, but a defendant was able to wage his law and the sum claimed had to be a sum certain fixed at the date of contract. Such rules could easily work hardship. What if a promisor (A) orally agreed to supply grain to a promisee (B), but failed to do so? In such a case, B would be unable to bring a writ of covenant due to the absence of a deed. B would instead bring debt sur contract, bringing a number of transaction witnesses. But what if A elected wager of law and simply hired his eleven oath-helpers? Emergence of assumpsit Litigants began to turn from the praecipe writs of covenant and debt to the ostensurus quare writ of trespass. By the middle of the 14th century the royal courts were recognising that a writ of trespass would lie even without an allegation that the defendant had