 As a longer term and more significant development , the Bill of Middlesex was one of several revolutionary developments by the King 's Bench met with a conservative reaction from the Common Pleas , fearful of losing its own caseload . The troubles during this period are best illustrated by Slade 's Case . 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 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 , the Chief Justice of the King 's Bench , John Popham , deliberately provoked the Common Pleas into bringing an assumpsit action to a higher court where the Justices of the King 's Bench could vote , allowing them to overrule the Common Pleas and establish assumpsit as the main contractual action . After the death of Edmund Anderson , the more activist Francis Gawdy became Chief Justice of the Common Pleas , which briefly led to a less reactionary and more revolutionary Common Pleas . 
