Praefectus Urbi

The ''praefectus urbanus'', also called ''praefectus urbi'' or urban prefect in English, was prefect of the city of Rome, and later also of Constantinople. The office originated under the Roman kings, continued during the Republic and Empire, and held high importance in late Antiquity. The office survived the collapse of the Western Roman Empire, and the last urban prefect of Rome, named Iohannes, is attested in 599. Lançon (2000), p. 45 In the East, in Constantinople, the office survived until the 13th century.

Regal period

According to Roman tradition, in 753 BC when Romulus founded the city of Rome and instituted the monarchy, he also created the office of ''custos urbis'' (guardian of the city) to serve as the king's chief lieutenant. Appointed by the king to serve for life, the ''custos urbis'' served concurrently as the ''princeps Senatus''. As the second highest office sof state, the ''custos urbis'' was the king's personal representative. In the absence of the king from the city, the ''custos urbis'' exercised all of his powers, which included the powers of convoking the Senate, the popular assemblies and the exercise of force in the event of an emergency. However, the ''imperium'' he possessed was only valid within the walls of Rome.

Under the kings, only three men held the position. The first king Romulus appointed Denter Romulius to serve as the first ''custos urbis'', the third king Tullus Hostilius appointed Numa Marcius, and the seventh king Tarquinius Superbus appointed Spurius Lucretius.

Republican period

After the expulsion of Tarquinius Superbus in 510 BC and the formation of the Republic in 509 BC, the office of ''custos urbis'' remained unaltered: having power only within the actual city of Rome and a life term appointed by the consuls. The ''custos urbis'' exercised within the city all the powers of the consuls if they were absent from Rome. These powers included: convoking the Senate and '' Comitia Curiata'', and, in times of war, levying and commanding legions.

The first major change to the office occurred in 487 BC, when the office became an elective magistracy, elected by the ''Comitia Curiata''. The office was only open to former consuls. Around 450 BC, with the coming of the decemvirs, the office of the ''custos urbis'' was renamed the ''praefectus urbi'' (Prefect of the City of Rome), and was stripped of most of its powers and responsibilities, becoming a merely ceremonial post. Most of the office's powers and responsibilities had been transferred to the urban praetor ('' praetor urbanus''). The ''praefectus urbi'' was appointed each year for the sole purpose of allowing the consuls to celebrate the Latin Festival, which required them to leave Rome. The ''praefectus urbi'' no longer held the power to convoke the Senate, or the right of speaking in it, and was appointed by the Consuls instead of being elected.

Imperial period

Rome

When the first Roman Emperor, Augustus (), transformed the Roman Republic into the Roman Empire in 27 BC, he reformed the office of Prefect at the suggestion of his minister and friend Maecenas. Again elevated into a magistracy, Augustus granted the ''praefectus urbi'' all the powers needed to maintain order within the city. The office's powers also extended beyond Rome itself to the ports of Ostia and the Portus, as well as a zone of one hundred Roman miles (c. 140 km) around the city. The Prefect's office was called the ''secretarium tellurense'' (secretariat of Tellus). The find-spots of inscriptions honouring Prefects suggest that it was located on the Oppian Hill, near the Baths of Trajan. Acting as a quasi-mayor of Rome, the Prefect was the superintendent of all guilds and corporations (''collegia''), held the responsibility (via the '' praefectus annonae'') of the city's provision with grain from overseas, the oversight of the officials responsible for the drainage of the Tiber and the maintenance of the city's sewers and water supply system, as well as its monuments. The provisioning of the city's large population with the grain dole was especially important; when the Prefect failed to secure adequate supplies, riots often broke out.

To enable the Prefect to exercise his authority, the '' cohortes urbanae'', Rome's police force, and the nightwatchmen ('' vigiles'') under their prefect (''praefectus vigilum''), were placed under his command.Lançon (2000), p. 46 The Prefect also had the duty of publishing the laws promulgated by the Emperor, and as such acquired a legal jurisdiction. This extended to legal cases between slaves and their masters, patrons and their freedmen, and over sons who had violated the '' pietas'' towards their parents. Gradually, the judicial powers of the Prefect expanded, as the Prefect's office began to re-assume its old powers from the ''praetor urbanus''. Eventually there was no appeal from the Prefect's sentencing, except to that of the Roman Emperor, unlike the sentencing of other officials. Even the governors of the Roman provinces were subject to the Prefect's jurisdiction. The Prefect also possessed judicial powers over criminal matters. Originally these powers were exercised in conjunction with those of the quaestors, but by the 3rd century, they were exercised alone.

In late Antiquity, the office gained in effective power, as the imperial court was removed from the city, meaning that the prefects were no longer under the emperor's direct supervision. The office was usually held by leading members of Italy's senatorial aristocracy, who remained largely pagan even after Emperor Constantine the Great's conversion to Christianity. Over the following thirty years, Christian holders were few.Kazhdan (1991), p. 2144 In such a capacity, Quintus Aurelius Symmachus played a prominent role in the controversy over the