Before the reforms of the Judicature Act 1873, civil cases at common law were begun in one of the three courts that sat in Westminster Hall: the Court of Common Pleas, Court of Exchequer and King's Bench. Because of their historical origins, these courts were to some extent in competition, especially as their respective judges and officers lived off the fees. However, in medieval times, travel to London was an onerous burden so in 1285 the Statute of Westminster II provided for trial of fact in civil cases at the local assizes. Nisi prius translates as "unless sooner" or "unless before" and, when the action was started in London, the sheriff was ordered to have the jurors there for trial on a certain day "unless before" (nisi prius) that day the case was heard at assize in the claimant's county. After trial at the assizes, the case could be referred back to the original court, from where there was a possibility of further appeal to the Court of Exchequer Chamber.
After the reform of the common law courts in 1873, actions were only said to be tried at nisi prius, and a judge said to sit at nisi prius, when he sat, usually in the King's Bench Division, for the trial of actions. By a resolution passed by the judges of the King's Bench Division in 1894 it was declared of the utmost importance that there should be at least three courts of nisi prius sitting continuously throughout the legal year: one for special jury causes, one for common jury causes, and one for causes without juries.