Istanbul, formerly called Constantinople, is Turkey’s largest city and serves as its economic, cultural and historic center. It spans the Bosporus Strait, connecting Europe and Asia, and has a population of over 15 million residents, comprising 19% of Turkey’s population. Istanbul is Europe’s most populous city[c] and the world’s 15th-largest city.

The city of Byzantium (Greek: Βυζάντιον, Byzantion) was founded in the 7th century BCE by Greek settlers from Megara. In 330 CE, the Roman Emperor Constantine the Great made it the imperial capital, giving it the name New Rome, and later renamed it Constantinople (Constantinopolis) after himself. In 1930, the name of the city was officially changed to Istanbul. It was previously known as to the City, a name used by Greek speakers colloquially since the 11th century. The new name ‘Istanbul’ is the Turkish rendering of the previous name.

The city acted as an imperial capital for almost 1600 years, during the Roman/Byzantine (330–1204), Latin (1204–1261), late Byzantine (1261–1453), and Ottoman (1453–1922) empires. Throughout this period, the city expanded in size and influence and eventually became a prominent hub of the Silk Road, establishing itself as one of the most significant cities in history.

The city has had a significant impact on the development of Christianity during Roman/Byzantine times, having hosted four of the first seven ecumenical councils. After the fall of Constantinople in 1453 CE, the city was transformed into an Islamic stronghold, especially after the Ottoman Caliphate made it its capital in 1517. In 1923, following the Turkish War of Independence, the city was replaced by Ankara as the capital of the newly formed Republic of Turkey.

In 2018, Istanbul welcomed over 13.4 million foreign visitors, securing its place as the eighth most visited city worldwide. The city earned the title of European Capital of Culture eight years prior to this. The historic centre of Istanbul is recognized as a UNESCO World Heritage Site. Furthermore, the city accommodates the headquarters of numerous Turkish companies, which account for over thirty percent of the country’s economy.


The city’s initial name was Byzantium when it was established by Megarian colonists circa 657 BCE. The colonists traced their lineage to the city’s founders, Byzas, the son of Poseidon and the nymph Ceroëssa. Recent archaeological discoveries have suggested that the name Byzantium may have been derived from pre-existing Thracian settlements. Constantinople derives from the Latin name Constantinus, named after Constantine the Great, the Roman emperor who recast the city in 324 AD. The name Constantinople remained prevalent in the West until the 1930s, when Turkish authorities aimed to promote the term “Istanbul” in foreign languages. During Ottoman rule, Ḳosṭanṭiniye and İstanbul were the two names alternatively used by the Ottomans.

İstanbul is the current name for the city. Istanbul is believed to have originated from the Medieval Greek phrase, meaning “to the city”. This is how Constantinople was referred to by the local Greeks, reflecting its status as the only significant city in the surrounding area. Constantinople’s significance in the Ottoman Empire is apparent with its nickname ‘Der Saadet,’ meaning ‘Gate to Prosperity’ in Ottoman Turkish. Another perspective suggests the name comes directly from ‘Constantinople,’ omitting the first and third syllables.

Ottoman sources from the 17th century, including Evliya Çelebi, describe it as the common Turkish name of the period. Its official use spanned from the late 17th to the late 18th century. The term Islambol initially appeared on coinage in 1730, during the reign of Sultan Mahmud I. Nowadays, the name is written as İstanbul in modern Turkish, whereby the Turkish alphabet distinguishes between a dotted and dotless I – the latter of which appears in the word Istanbul. Although the stress in English is placed on either the first or last syllable, the stress in Turkish falls on the second syllable (-tan-). A native of the city is referred to as an İstanbullu, whereas in English, Istanbulite is commonly used.

Istanbul History

Neolithic artefacts, discovered by archaeologists in the early 21st century, suggest that Istanbul’s historical peninsula was inhabited as early as the 6th millennium BCE. This early settlement played a significant role in the dissemination of the Neolithic Revolution from the Near East to Europe and lasted for almost a thousand years before being submerged by rising water levels.

The Fikirtepe mound represents the first known human settlement on the Asian side of Istanbul, dating back to the Copper Age period between 5500 and 3500 BCE. Additionally, in the early 1st millennium BCE, a Thracian settlement was present near the peninsula’s point in Sarayburnu on the European side. This site is believed to have been referred to as Lygos in ancient texts, including Pliny the Elder’s accounts of Byzantium.

The origins of the city date back to approximately 660 BCE, when Byzantium was founded on the European side of the Bosporus by Greek settlers from Megara. The settlers constructed an acropolis near the Golden Horn, on the location of early Thracian settlements. This helped to boost the economy of the developing city. A brief period of Persian rule occurred in the 5th century BCE but the Greeks regained control during the Greco-Persian Wars. Byzantium subsequently remained part of the Athenian League and then the Second Athenian League before achieving independence in 355 BCE.

Byzantium had long been allied with the Romans and officially became a part of the Roman Empire in 73 CE. However, its decision to support the Roman usurper Pescennius Niger against Emperor Septimius Severus proved to be costly as the city was left devastated at the end of the two-year siege in 195 CE. Five years later, Severus initiated the rebuilding of Byzantium, which allowed the city to recover and even surpass its previous level of prosperity according to some sources.

Rise and fall of Constantinople and the Byzantine Empire

Constantine the Great became the undisputed emperor of the Roman Empire in September 324. Shortly thereafter, he unveiled his plans to construct a new city to replace Byzantium, which would be dedicated to the Christian faith. The city, known as Nova Roma to some but more commonly referred to as Constantinople, served as the eastern capital of the Roman Empire. This name persisted into the 20th century. On 11 May 330, Constantinople was officially proclaimed as the new capital of the Roman Empire. Later, upon the death of Theodosius I on 17 January 395, the empire was permanently divided between his two sons, and Constantinople became the capital of the Eastern Roman (Byzantine) Empire.

The founding of Constantinople was among Constantine’s most enduring achievements, relocating Roman influence towards the east as the metropolis emerged as a hub of Greek culture and Christianity. Countless places of worship were constructed throughout the urban centre, including Hagia Sophia, which was erected during the reign of Justinian the Great and held the title of the world’s largest cathedral for a millennium. In the 4th century, Constantine implemented a significant renovation and expansion of the Hippodrome of Constantinople. With the capacity to accommodate tens of thousands of spectators, the Hippodrome was a focal point of civic life. However, in the 5th and 6th centuries, it also became the centre of several instances of unrest, including the Nika riots.

Constantinople’s location ensured its longevity, protecting Europe’s eastern border from invaders and the advance of Islam for many centuries through its formidable walls and seafront. During the later part of the Byzantine era, it was Europe’s largest and wealthiest city, at times surpassing every other in the world. Today, Constantinople remains the hub of Orthodox Christian civilization, often regarded as its birthplace.

Constantinople’s decline began after Basil II’s reign ended in 1025. The Fourth Crusade deviated from its intended target in 1204, resulting in the city’s plunder and pillage by the Crusaders. Consequently, the Latin Empire replaced the Orthodox Byzantine Empire. Additionally, Hagia Sophia had been converted to a Catholic church by 1204. The Byzantine Empire was re-established in 1261, although its strength was diminished. Constantinople had neglected churches, defenses, and other essential services while its population had decreased from half a million to a hundred thousand since the 8th century. Following the recapture in 1261, a few of the city’s landmarks were renovated and some new pieces were commissioned, such as the Deesis Mosaic in Hagia Sophia and Kariye.

Several economic and military policies enacted by Andronikos II, including the downsizing of military forces, resulted in a weakened state for the empire, rendering it susceptible to attacks. In the mid-14th century, the Ottoman Turks adopted a plan of slowly taking over smaller towns and cities, severing the supply routes to Constantinople, and strangling the city’s resources. Sultan Mehmed II “the Conqueror” captured Constantinople on 29 May 1453 after an eight-week siege that resulted in the death of the last Roman emperor, Constantine XI. Following this victory, he declared Constantinople as the new capital of the Ottoman Empire.

Hours later, the sultan rode to the Hagia Sophia and summoned an imam to declare the Islamic creed, converting the grand cathedral into an imperial mosque due to the city’s refusal to surrender peacefully. Mehmed declared himself as the new Kayser-i Rûm (the Ottoman Turkish equivalent of the Caesar of Rome) and the Ottoman state was reorganized into an empire.

Ottoman Empire and Turkish Republic eras

Following the capture of Constantinople, Mehmed II wasted no time in rejuvenating the city. Aware that the revival of the city was contingent upon its repopulation, Mehmed II displayed remarkable openness and willingness to integrate outsiders, including foreigners, criminals, and runaways, thereby embodying values that shaped the Ottoman political culture. In addition, he invited people from various parts of Europe to his capital, contributing to the establishment of a cosmopolitan society that lasted for much of the Ottoman era.

The restoration of Istanbul also necessitated a comprehensive scheme, spanning from roads to aqueducts. Mehmed II is one of many monarchs who have transformed Istanbul’s urban landscape through extensive redevelopment of the city centre. In addition to a new palace of significant proportions that rivalled if not surpassed the old one, the construction of a covered market (which still exists as the Grand Bazaar), porticoes, pavilions, walkways, and over a dozen new mosques were erected. Consequently, the ramshackle old town was transformed into a capital that exuded magnificence and splendor.

The bubonic plague of the 16th century spared no one, disregarding social status as both the wealthy and the poor perished at its hands. Financial wealth could not shield the rich from the afflictions and adversities of Istanbul. Although the Sultan resided at a safe distance from the masses, and the affluent and destitute coexisted in proximity, modern urban planning was not a common practice in Istanbul. Opulent houses shared the same streets and districts as small hovels. Wealthy individuals who possessed secluded country properties had the opportunity to avoid the periodic epidemics of sickness that ravaged Istanbul.

The Ottoman Dynasty declared itself the caliphate in 1517, with Constantinople serving as the capital of this final caliphate for four centuries. During Suleiman the Magnificent’s reign from 1520 to 1566, there was a distinctive period of great artistic and architectural success, with chief architect Great Architect Sinan designing a number of memorable structures in the city, while Ottoman arts of ceramics, stained glass, calligraphy, and miniature painting prospered. By the conclusion of the eighteenth century, the population of Constantinople had reached 570,000.

At the outset of the 19th century, there was a period of rebellion that led to the ascent of Sultan Mahmud II, a progressive reformer. His rise to power eventually brought about the Tanzimat era, which instated political reforms and facilitated the introduction of new technologies in the city. Bridges spanning the Golden Horn were also built during this period. Additionally, Constantinople was integrated with the greater European railway network in the 1880s. Constantinople saw the gradual introduction of modern amenities, including a water supply network, electricity, telephones, and trams, over the subsequent decades, albeit later than other European cities. Despite these modernization efforts, they failed to avert the decline of the Ottoman Empire.

In 1908, the Young Turk Revolution resulted in the deposition of Sultan Abdul Hamid II and the reopening of the Ottoman Parliament, which had been closed since February 14th, 1878. This event marked the beginning of the Second Constitutional Era. The empire’s capital was plagued by a series of wars in the early 20th century, including the Italo-Turkish War (1911-1912) and the Balkan Wars (1912-1913), ultimately leading to the 1913 Ottoman coup d’état and the rise of the Three Pashas regime.

The Ottoman Empire aligned with the Central Powers and entered World War I spanning from 1914 to 1918. Ultimately, it faced defeat. The forced migration of Armenian intellectuals on 24th April 1915 was one of the significant incidents that initiated the Armenian genocide during WWI (81). From 1914 to 1927, the Christian population of the city decreased from 450,000 to 240,000.

This outcome was due to the Turkification and ethnic cleansing policies enforced by the Ottoman and Turkish regimes (82). The Allies took control of Constantinople on 13th November 1918, following the signing of the Armistice of Mudros on 30th October 1918. The Allies dissolved the Ottoman Parliament on 11th April 1920, leading to the Ottoman delegation led by Damat Ferid Pasha being compelled to sign the Treaty of Sèvres on 10th August 1920.

After the Turkish War of Independence (1919-1922), the Grand National Assembly of Turkey situated in Ankara abolished the Sultanate on 1 November 1922. The last Ottoman Sultan, Mehmed VI, was declared a persona non grata and departed aboard the British warship HMS Malaya on 17 November 1922 to go into exile. He died on 16 May 1926, in Sanremo, Italy.

The Treaty of Lausanne was signed on 24th July 1923, and the occupation of Constantinople came to an end with the withdrawal of the last Allied forces from the city on 4th October 1923. Turkish forces of the Ankara government, under the command of Şükrü Naili Pasha of the 3rd Corps, ceremoniously entered Istanbul on October 6th, 1923 to mark its liberation, an event commemorated annually on the same date. On October 29th, 1923, the Grand National Assembly of Turkey declared Ankara as the capital of the newly established Turkish Republic, with Mustafa Kemal Atatürk becoming the Republic’s first President.

In 1942, a wealth tax aimed primarily at non-Muslims resulted in the transfer or liquidation of numerous businesses owned by religious minorities. Istanbul experienced significant structural transformation from the late 1940s and early 1950s, with the construction of new public squares, boulevards, and avenues throughout the city, occasionally at the cost of historical buildings. The population of Istanbul experienced a significant surge in the 1970s when individuals from Anatolia migrated towards the city to seek employment in novel factories erected on the edges of the sprawling metropolis. This sharp escalation in the city’s inhabitants engendered a substantial requirement for housing, and numerous villages and forests that were formerly situated on the outskirts integrated into the metropolitan area of Istanbul.

Istanbul Geography

Istanbul, positioned in north-western Turkey, lies across the Bosporus Strait, serving as the exclusive channel connecting the Black Sea to the Mediterranean through the Sea of Marmara. The city’s advantageous location has facilitated its significance for trade and defense throughout history. The meeting of the Sea of Marmara, the Bosporus, and the Golden Horn provides excellent defense against enemy attacks and a natural gateway. Several charming islands, including Buyukada, Heybeliada, Burgazada, Kinaliada, and five smaller islands, are incorporated into the city. Istanbul’s coastline has been expanded beyond its boundaries. Large portions of Caddebostan exist on landfill areas, resulting in a total city area of 5,343 square kilometers (2,063 sq mi).

Despite the commonly held belief that Istanbul is built on seven hills, it is actually spread across more than 50 hills within the city limits.

Aydos is the highest of these hills, rising 537 meters (1,762 ft) above sea level. Although it does not run through the city, the nearby North Anatolian Fault is responsible for a significant amount of seismic activity in the region, and it is highly probable that an earthquake of at least magnitude 7 will occur in the area before 2030, with a very high likelihood of one happening in the 21st century.

This fault was responsible for the earthquakes that occurred in 1766 and 1894. The possibility of serious earthquakes has significantly influenced the city’s infrastructure development, leading to the demolition and replacement of over 500,000 vulnerable buildings since 2012. The city has regularly revised its building codes, with the latest update taking place in 2018, mandating retrofits for older structures[citation needed and more advanced engineering standards for new constructions.

Istanbul Climate

Istanbul boasts of a temperate climate, often described as a transition between Turkey’s western and southern coasts’ Mediterranean climate and the northwestern coastal area’s oceanic climate. However, there is a significant variance in the classification terminology used for the city’s climate.

During summers, the city experiences moderately dry and warm to hot weather, with daytime temperatures averaging 27 °C (81 °F), and less than seven days of precipitation in a month. Although the temperature range is typically acceptable, mid-summer in Istanbul is moderately uncomfortable due to high dew points and relative humidity . Winters are characteristically cool, quite rainy, and relatively snow-rich for a city with above-freezing average temperatures.

Istanbul experiences uneven precipitation, with winter months receiving at least twice as much precipitation as summer months.

The mode of precipitation also varies by season. Winter precipitation is typically light, persisting and frequently a mix of rain, snow and graupel. On the other hand, summer rainfall is typically sudden and sporadic. The level of cloudiness, like precipitation, varies considerably by season, with winters typically being relatively cloudy, characterized by roughly 20% of days being sunny or partly cloudy. In contrast, summers have 60-70% of possible sunshine.

Snowfall in the region is infrequent, however, accumulates each winter, causing persistent and disruptive effects. Annual sea-effect snowstorms produce over 30 centimetres (1 ft) of snow, with the latest occurrence being in 2022.[95][96]

Istanbul European side

The district of Fatih, named after Fatih Sultan Mehmed, corresponds to the entirety of the city of Constantinople prior to the Ottoman conquest in 1453. It is now the capital district known as the historic peninsula of Istanbul, situated on the southern shore of the Golden Horn, opposite the medieval Genoese citadel of Galata on the northern shore. The Genoese fortifications in Galata were predominantly dismantled in the 19th century to allow for the city’s northward expansion, resulting in solely the Galata Tower remaining. Galata or Karakoy, as it is now known, constitutes a district in the Beyoğlu (Pera) area, which forms Istanbul’s commercial and entertainment centre, incorporating İstiklal Avenue and Taksim Square.

Dolmabahce Palace, which served as the seat of government in the late Ottoman era, is situated in the Beşiktaş neighbourhood on the European bank of the Bosporus strait, to the north of Beyoglu. Within the bounds of Beşiktaş lies the quaint village of Ortakoy, which lends its name to the Ortakoy Mosque situated along the Bosporus in proximity to the Bosporus Bridge.

Luxurious chalet mansions, known as historic yalıs and originally built as summer homes by Ottoman aristocrats and elites, decorate both the Asian and European sides of the Bosporus. Moving inland, north of Taksim Square is the Istanbul Central Business District, which consists of corridors adorned with office buildings, residential towers, shopping centres, and university campuses, and boasts a total of over 2,000,000 m2 (22,000,000 sq ft) of class-A office space. Maslak, Levent, and Bomonti are significant areas within the CBD (Central Business District) in Istanbul.

Another notable edge city-style business, residential, and shopping corridor is the Atatürk Airport corridor, boasting a vast expanse of over 900,000 m2 (9,700,000 sq ft) of class-A office space.

Istanbul Asian side

During the Ottoman era, Uskudar (previously Scutari) and Kadikoy lay beyond the boundaries of the urban region, acting as peaceful enclaves featuring coastal mansions and gardens. In the latter half of the 20th century, significant urban expansion occurred on the Asian side of Istanbul, resulting in improved infrastructure and more organized urban planning when contrasted with other residential zones in the city.

A sizable proportion of the Bosporus’ Asian side serves as a suburban area for the financial and commercial hubs in European Istanbul, representing one-third of the city’s population but only a quarter of its workforce. Kozyatagi-Atasehir, Altunizade, Kavacik, and Umraniye collectively possess around 1.4 million square meters of class-A office space, making them significant “edge cities.” These locations serve as corridors and nodes for business, shopping centers, and tall residential buildings.