When did common law originate?
Common law
The common law—so named because it was "common" to all the king's courts across England—originated in the practices of the courts of the English kings in the centuries following the Norman Conquest in 1066.[10] The British Empire spread the English legal system to its historical colonies, many of which retain the common law system today. These "common law systems" are legal systems that give great precedential weight to common law, and to the style of reasoning inherited from the English legal system.[11][12][13][14]
Subpoena ad testificandum
Until the Late Middle Ages it was not apparent to contemporaries that there would be, or could be, two different and competing legal systems in England, one of them common law and the other equity. They were, however, aware of the conflicting courts. There was a conflict of jurisdiction. There were numerous complaints that various authorities had exceeded their power. Equity grew in its desire to deal with the "de facto" failings of the common law courts, and did not concern itself with doctrinal differences. Often, a suitor who was dissatisfied with the result in a common law court would refile the case in Equity or Chancery. These latter courts saw their role as being "equalizers": socially, legally, economically. In this position, and encouraged by Roman law traditions, they were always creative in producing new writs which could not be found in the common law courts. It was in this spirit that Justice Berrewyk in 1302, ordered an infant to be brought before the court with a writ subpoena: "under pain of (forfeit) of 100 pounds". But there is evidence that "threat of penalty" had been attached to writs used by the government to induce behavior as early as 1232. By 1350, the writ certis de causis (the "writ for certain causes"), began having the clause subpoena routinely attached. The writ quibusdam certis de causis is at least as old at 1346, and had subpoena attached. The great objection which common lawyers made to writs in this form was their failure to mention the cause of the summons. It became the custom in the common law courts that the person would not be compelled to appear without having notice of the reasons for appearing. Early subpoenas carried no notice of the reason for the summons. Objections in Parliament became loud and frequent. On the one hand, Chancery believed that a wrongdoer might engage in maintenance to prepare the verdict before appearing in court. On the other side, common law courts found it difficult to amend the presented writ, and many cases were lost for want of the correct writ at the beginning of the case.