Slade's Case (or Slade v. Morley) was a case in English contract law that ran from 1596 to 1602. Under the medieval common law, claims seeking the repayment of a debt or other matters could only be pursued through a writ of debt in the Court of Common Pleas, a problematic and archaic process. By 1558 the lawyers had succeeded in creating another method, enforced by the Court of King's Bench, through the action of assumpsit, which was technically for deceit. The legal fiction used was that by failing to pay after promising to do so, a defendant had committed deceit, and was liable to the plaintiff. The conservative Common Pleas, through the appellate court the Court of Exchequer Chamber, began to overrule decisions made by the King's Bench on assumpsit, causing friction between the courts. In Slade's Case, a case under assumpsit, which was brought between judges of the Common Pleas and King's Bench, was transferred to the Court of Exchequer Chamber where the King's Bench judges were allowed to vote. The case dragged on for five years, with the judgment finally being delivered in 1602 by the Chief Justice of the King's Bench, John Popham. Popham ruled that assumpsit claims were valid, a decision called a "watershed" moment in English law, with archaic and outdated principles being overwritten by the modern and effective assumpsit, which soon became the main cause of action in contract cases. This is also seen as an example of judicial legislation, with the courts making a revolutionary decision Parliament had failed to make. Background Under the medieval common law, there was only one way to resolve a dispute seeking the repayment of money or other contract matters; a writ of debt, which only the Court of Common Pleas could hear. This was archaic, did not work against the executors of a will and involved precise pleading; a minor flaw in the documents put to the court could see the case thrown out. By the middle of the 16th century lawyers had attempted to devise an alternative using the action of assumpsit, which was technically a type of trespass due to deceit. The argument was based on the idea that there was an inherent promise in a contract to pay the money, and that by failing to pay the defendant had deceived the plaintiff. By 1558 the lawyers had succeeded, with the Court of King's