In the course of time, the office also took over the coordination of foreign affairs (already in the late 4th century, the official translators and interpreters were under the control of the "magister officiorum" for this reason), and in the East, the "Notitia" records the presence of four secretaries in charge of the so-called Bureau of Barbarians under the "magister"'s supervision. One of the most important incumbents of this office was Peter the Patrician, who held the position from 539 to 565 and undertook numerous diplomatic missions in this role for Emperor Justinian I (). The office was also retained in Ostrogothic Italy after the fall of the Western Roman Empire, and was held by eminent Roman senators such as Boethius and Cassiodorus.