SUBPOENA, practice, evidence. A process to cause a witness to appear and give testimony, commanding him to lay aside all pretences and excuses, and appear before a court or magistrate therein named, at a time therein mentioned, to testify for the party named, under a penalty therein mentioned. This is usually called a subpoena ad testificandum.
SUBPOENA, chancery practice. A mandatory writ or process, directed to and requiring one or more persons to appear at a time to come, and answer the matters charged against him or them; the writ of subpoena was originally a process in the courts of common law, to enforce the attendance of a witness to give evidence; but this writ was used in the court of chancery for the game purpose as a citation in the courts of civil and canon law, to compel the appearance of a defendant, and to oblige him to answer upon oath the allegations of the plaintiff.
2. This writ was invented by John Waltham, bishop of Salishury, and chancellor to Rich. II. under the authority of the statutes of Westminster 2, and 13 Edw. I. c. 34, which enabled him to devise new writs. 1 Harr. Prac. 154; Cruise, Dig. t. 11, c. 1, sect. 12-17. Vide Vin. Ab. h. t.; 1 Swanst. Rep. 209.