The ancient city of Constantinople was divided into 14 administrative regions (Latin: regiones, Greek: συνοικιες, romanized: synoikies). The system of fourteen regiones was modelled on the fourteen regiones of Rome, a system introduced by the first Roman emperor Augustus in the 1st century AD.
After Emperor Constantine the Great re-founded Byzantium as Constantinople and Nova Roma ('New Rome') in the early 4th century, he or his immediate successors divided Constantinople into its own 14 regiones. Each region (regio) was numbered, and their boundaries and landmarks in the 5th century were enumerated by the Notitia Urbis Constantinopolitanae, which also gives details of the city's Cura Annonae, the public grain ration which was distributed by regio. Two regiones, XIII and XIV, were outside the original city walls.