This text is a fragment of a guidebook to Istanbul: "Byzantine Secrets of Istanbul".

It is well known that all roads should lead to Rome, but when the capital of the Roman Empire was moved to Constantinople in the 4th century, this city also became the benchmark for measuring distances within the empire. While in Rome the role of the zero milestone was played by the Milliarium Aureum, or the Golden Milestone, in Constantinople it was assigned to the Milion. It was a monument from which all road distances to the cities of the Empire were measured. Nowadays, only very modest remains of this structure can be seen in Istanbul near the entrance to the famous Basilica Cistern.

The idea of marking a zero milestone in the Roman Empire was first implemented at the Forum Romanum in Rome. There were not one but two structures with a similar role. The first of them -- Umbilicus Urbis Romae, or the Navel of the City of Rome -- was the symbolic centre of the capital, and thus of the entire Roman state. The second one was the Milliarium Aureum, built during the reign of the first emperor, Augustus, around 20 BCE. Only small fragments have survived from both monuments, not reflecting their former glory.

When Emperor Constantine the Great moved the capital of the Empire to the city of Byzantium, which he renamed as Nova Roma, he introduced many solutions known from Rome. One of them was the zero milestone, which was now to mark the centre of the empire and serve as a reference point for measuring distances. This building, known as the Milion, was erected in the heart of the city, in its first region, right at the beginning of the city's most important thoroughfare called the Mese. In the immediate vicinity there was also Augustaion, the most important square of the city, which is now represented by Aya Sofya Meydanı -- Hagia Sophia Square.

The Milion was in the form of a tetrapylon, i.e. a quadruple arch, a monumental gate with four entrances, traditionally placed at road crossings or on forums. A better idea of how the tetrapylon should appear can be obtained by looking at the much better preserved buildings of this type, such as the Monumental Gate in Aphrodisias or the Arch of Janus in Rome. The tetrapylon in Constantinople was covered by a dome vault, and its role as the zero milestone was reflected in the inscriptions recording distances to all the major cities of the empire.

Originally, the Milion was decorated with the statues of Emperor Constantine and his mother Helena, with a cross between them. They were accompanied by the goddess Tyche in the role of the patron deity of Constantinople. Over the centuries, successive emperors introduced their modifications and additions to the Milion. Numerous sculptures were erected near the monument, including equestrian statues of the most famous Roman emperors -- Trajan and Hadrian -- whose rule in the 2nd century marked the golden years of the Roman Empire. Perhaps they were later joined by the equestrian statue of Theodosius II, who erected the Theodosian Walls in 412-439, making Constantinople the largest and most powerful stronghold of the world at that time.

In the 6th century, the Milion began to play an increasingly important role in state ceremonies. During this period, Emperor Justinian I added a horologion, or sundial, to the structure. Justinian's nephew, Emperor Justin II, ordered the Milion to be decorated with female statues depicting his wife Sophia, daughter Arabia, and niece Helena. We know these facts only thanks to the writings of Georgios Kedrenos, a Byzantine chronicler from the 11th century.

Women played a huge role in Justin II's life. First, the wife of Emperor Justinian, Empress Theodora, initiated the marriage of her niece, Sophia, with Justin. When Justin II became the emperor, he developed symptoms of a mental illness, such as hearing voices, seeing demons, and fits of aggression. These symptoms may indicate that this ruler suffered from schizophrenia. Due to his deteriorating health, the emperor was forced by his wife, Sophia, to appoint a successor. He chose general Tiberius for this role, whom he formally adopted. For the last four years of Justin II's life, it was Sophia and Tiberius who ruled the empire as co-regents.

The sculptures and paintings adorning the Milion reflected the changing politics and religious beliefs of Byzantium. For example, in the first half of the 8th century, the vault of the building was covered with paintings depicting the scenes from past ecumenical councils. They were commissioned by the emperors Philippikos Bardanes and Anastasios II. However, already in the middle of the 8th century, these paintings were removed because Emperor Constantine V was a supporter of iconoclasm and opposed the cult of images. This did not prevent him from commissioning the scenes of chariot racing at the hippodrome, including the ones depicting his favourite charioteer.

It was in the vicinity of the Milion where, during the imperial processions, the rulers were usually greeted by the representatives of the Blues -- one of the main racing teams of the city. At a time when Rome was the capital of the empire, there were four of these factions: the Blues, the Reds, the Greens, and the Whites. However, in Constantinople, the only significant teams were the Greens and the Blues. The Greens customarily represented the lower classes and unorthodox factions while the Blues represented the upper classes and the orthodox version of religion supported by the state.

The Milion was for centuries a silent witness to the most important events in Constantinople, such as the Nika revolt of 532, which was incited by the supporters of the Blues and the Greens. Much later, in 1081, the last acts of the power struggle between Nikephoros III Botaniates and Alexios I Komnenos took place in its vicinity. Empress Maria of Antioch, who was overthrown in 1182 by the city's population, dissatisfied with her regency, also fought a desperate struggle for power in this location.

The fate of the Milion during the late Byzantine era is uncertain. During the Latin occupation of the city in 1204-1261, the monument was damaged or even destroyed. Its preserved fragments were used after the Turkish conquest to expand the water supply system to the city in the 16th century.

Only the archaeological excavations carried out in 1967-1968, after the demolition of the residential houses in this location, discovered the foundations of the ancient building. Currently, the location of the Milion is marked by the re-erected fragment of one of its pillars. The Istanbul authorities have also placed a signpost in the vicinity, showing the distances to several important metropolises, such as Tehran, London, and Moscow.

This text is a fragment of a guidebook to Istanbul: "Byzantine Secrets of Istanbul".