The prefect was solely responsible for the administration of the city of Constantinople and its immediate area. His tasks were manifold, ranging from the maintenance of order to the regulation and supervision of all guilds, corporations and public institutions. The city police, the ("taxiōtai"), came under the prefect's authority, and the city jail was located at the basement of his official residence, the "praetorium", located before the Forum of Constantine. As with the Prefect of Rome, the night watch came under a subordinate prefect, the ("nykteparchos", "night prefect"). In the 530s, however, some authority for the policing and regulation of the city passed to two new offices, created by Justinian I (r. 527–565). In 535 the "praitōr" of the "demoi" (; "praetor plebis" in Latin), who commanded 20 soldiers and 30 firemen, was put in charge of policing and firefighting, while in 539, the office of the "quaesitor" (κοιαισίτωρ) was established and tasked with limiting the uncontrolled immigration to the city from the provinces, with supervising public mores, and with persecuting sexual offenders and heretics.