Abbreviator, plural Abbreviators in English or Abbreviatores in Latin, also called Breviators, were a body of writers in the papal chancery, whose business was to sketch out and prepare in due form the pope's bulls, briefs and consistorial decrees before these are written out in extenso by the scriptores.
They are first mentioned in the papal bulls Extravagantes of Pope John XXII and of Pope Benedict XII.
After the protonotaries left the sketching of the minutes to the abbreviators, those de Parco majori, who ranked as prelates, were the most important officers of the apostolic chancery. By the time of Pope Martin V their signature was made essential to the validity of the acts of the chancery; and they obtained in course of time many important privileges.
Read more about Abbreviator: Roman Lay Origin, Ecclesiastical Abbreviatores, Erection Into A College of Prelates, Titles and Privileges, Suppression