Milion

The Milion was a marker from which all distances across the Roman Empire were measured. Erected by Septimius Severus in the 3rd century AD in the city of Byzantium, it became the zero-mile marker for the empire upon the re-founding of the city as Constantinople in 330 AD. Thereafter, it would serve as the starting-place for the measurement of distances for all the roads leading to the cities of the Eastern Roman Empire. It thus served the same function as the Golden Milestone (Milliarium Aureum) in Rome's forum, erected by Augustus.

From Wikipedia, CC BY-SA 4.0.

• history