Constantinople is an ancient city in modern-day Turkey that’s now known as Istanbul. First settled in the seventh century B.C., Constantinople developed into a thriving port thanks to its prime geographic location between Europe and Asia and its natural harbor. In A.D. 330, it became the site of Roman Emperor Constantine’s “New Rome,” a Christian city of immense wealth and magnificent architecture. Constantinople stood as the seat of the Byzantine Empire for the next 1,100 years, enduring periods of great fortune and horrific sieges, until being overrun by Mehmed II of the Ottoman Empire in 1453.


In 657 B.C., the ruler Byzas from the ancient Greek city of Megara founded a settlement on the western side of the Strait of Bosporus, which linked the Black Sea with the Mediterranean Sea. Thanks to the pristine natural harbor created by the Golden Horn, Byzantium (or Byzantion) grew into a thriving port city.

Over the following centuries, Byzantium was alternately controlled by the Persians, Athenians, Spartans and Macedonians as they jockeyed for power in the region. The city was destroyed by Roman Emperor Septimius Severus around A.D. 196, but subsequently was rebuilt with some of the structures that survived into the Byzantine Empire, including the Baths of Zeuxippus, the Hippodrome and a protective wall.

After defeating his rival Licinius to become sole emperor of the Roman Empire in A.D. 324, Constantine I decided to establish a new capital at Byzantium called “Nova Roma”—New Rome.

Constantine I

Constantine set about expanding the territory of old Byzantium, dividing it into 14 sections and constructing a new outer wall. He lured noblemen through gifts of land, and transferred art and other ornaments from Rome for display in the new capital. Its wide avenues were lined by statues of great rulers like Alexander the Great and Julius Caesar, as well as one of Constantine himself as Apollo.

The emperor also sought to populate the city through offering residents free food rations. With a system of aqueducts already in place, he ensured access to water through the widening city by the construction of the Binbirdirek Cistern.

In A.D. 330, Constantine established the city that would make its mark in the ancient world as Constantinople, but also would become known by other names, including the Queen of Cities, Istinpolin, Stamboul and Istanbul. It would be governed by Roman law, observe Christianity and adopt Greek as its primary language, although it would serve as a melting pot of races and cultures due to its unique geographic location straddling Europe and Asia.

Justinian I

Justinian I, who reigned from A.D. 527 to 565, weathered the Nika Revolt early in his tenure and used the occasion to undertake extensive renovations of the city. He launched successful military campaigns that helped the Byzantines reclaim territories lost with the collapse of the Western Roman Empire in the fifth century, expanding its borders to encircle the Mediterranean Sea.

Additionally, Justinian established a uniform system of law with the Justinian Code, which would serve as a blueprint for civilizations to come.

Along with spurring the spread of iconoclasm in the Empire, Leo III (who ruled from A.D. 717 to 741) fought off an Arab siege of the city and stabilized the throne after recent years of upheaval. He was the first emperor of the Isurian dynasty.

Similarly, Basil I (who ruled from A.D. 867 to 886) launched what became the two-century-long Macedonian dynasty. Despite his illiteracy, he followed Justinian by undertaking renovations and attempting further codification of laws, and successfully pushed the empire’s borders south.


Constantinople endured for more than 1,100 years as the Byzantine capital in large part due to the protective wall completed under Theodosius II in 413. Expanding the city perimeter west from Constantine’s wall by approximately a mile, the new one stretched 3-1/2 miles from the Sea of Marmara to the Golden Horn.

A double set of walls was added after a series of earthquakes in the mid-fifth century, the inner layer standing some 40 feet high and studded with towers that reached another 20 feet.

The Hippodrome, originally built by Severus in the third century and expanded by Constantine, served as an arena for chariot races and other public events such as parades and displaying of the emperor’s captive enemies. More than 400 feet long, it's estimated to have seated up to 100,000 people.

Hagia Sophia

The Hagia Sophia marked a triumph of architectural design. Built on the site of former imperial churches by Justinian I, it was completed in less than six years by a workforce of 10,000 laborers. 

Four columns supported a massive dome with a diameter of more than 100 feet, while its polished marble and dazzling mosaics gave the Hagia Sophia the impression of always being brightly lit.

Less is known of Constantine’s Imperial Palace, which also figured prominently in the heart of the city, but it featured an elaborate display of mosaics, as well as a grand entrance known as the Chalke Gate.

Christian and Muslim Rule

While Constantine’s founding of New Rome coincided with efforts to establish Christianity as the state religion, that didn’t formally happen until after Theodosius I ascended to power in 379. He convened the First Council of Constantinople in 381, which supported the Council of Nicaea of 325, and declared the city patriarch as second in power only to Rome’s.

Constantinople became a center of the iconoclast controversy after Leo III in 730 outlawed the worshipping of religious icons. Although the Seventh Ecumenical Council of 787 reversed that decision, iconoclasm resumed as a rule of law less than 30 years later and lasted until 843.

With the Great Schism of 1054, when the Christian church split into Roman and Eastern divisions, Constantinople became the seat of the Eastern Orthodox Church, remaining so even after the Muslim Ottoman Empire took control of the city in the 15th century.

Fall of Constantinople

Famed for its immense wealth, Constantinople endured at least a dozen sieges over its 1,000-plus years as the Byzantine capital. These included attempts by Arab armies in the seventh and eighth centuries, as well as the Bulgarians and the Rus in the ninth and 10th centuries.

In the early 13th century, prior to heading to Jerusalem, the armies of the Crusades were diverted to Constantinople over a power struggle. When their promised payments fell through, they sacked the city in 1204 and established a Latin state.

Although the Byzantines reclaimed control of Constantinople in 1261, the city remained the sole major population center of what was now a shell of the empire.

Shortly after ascending to the Ottoman throne in 1451, Mehmed II began formulating plans for a major assault on Constantinople. With the overwhelming size of his armed forces, and additional advantages gained by the use of gunpowder, he succeeded where his predecessors failed, claiming Constantinople for Muslim rule on May 29, 1453.

Ottoman Rule

While the early decades of an Ottoman Empire-ruled Constantinople were marked by the transformation of churches into mosques, Mehmed II spared the church of the Holy Apostles and allowed a diverse population to remain.

Following the conqueror, the most prominent ruler of the Ottomans was Suleyman the Magnificent (who ruled from 1520 to 1566). Along with developing a series of public works, Suleyman transformed the judicial system, championed the arts and continued to expand the empire.

In the 19th century, the declining Ottoman state underwent major changes with the implementation of the Tanzimat Reforms, which guaranteed property rights and outlawed execution without a trial.


Early in the following century, the Balkan Wars, World War I and the Greco-Turkish War wiped out the remains of the Ottoman Empire.

The 1923 Treaty of Lausanne formally established the Republic of Turkey, which moved its capital to Ankara. Old Constantinople, long known informally as Istanbul, officially adopted the name in 1930.

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Constantinople/Istanbul.  The Simpson Center for the Humanities at the University of Washington.
Constantinople. Ancient History Encyclopedia.
The Age of Suleyman the Magnificent. National Gallery of Art, Washington.
Constantinople: City of the World’s Desire 1453-1924. Washington Post.
The Ecumenical Patriarchate of Constantinople. The Greek Orthodox Archdiocese of America.