Journey through 2,700 years of Istanbul's extraordinary history. From its founding as ancient Byzantium and its glory as Constantinople, capital of the Roman and Ottoman empires, to its transformation into modern-day Istanbul — discover the layers of civilization that make this city unique.
A City with 2,700 Years of History
Few cities on Earth can match Istanbul's historical depth and significance. Straddling two continents and commanding one of the world's most strategic waterways, this city has served as the capital of three great empires — the Roman, Byzantine, and Ottoman — and has been known by three legendary names: Byzantium, Constantinople, and Istanbul. Every street corner, mosque, church, wall, and palace tells a story spanning nearly three millennia. Understanding Istanbul's history transforms a visit from simple sightseeing into a profound journey through the foundations of Western and Eastern civilization. The Istanbul geographic page reveals the strategic location that made this city so coveted throughout the ages.
Ancient Byzantium (circa 660 BC – 330 AD)
Istanbul's story begins around 660 BC when Greek colonists from Megara, led by King Byzas, founded a settlement on the strategic peninsula where the Golden Horn meets the Bosphorus. According to legend, the Oracle at Delphi told Byzas to settle "opposite the blind" — referring to earlier colonists who had settled on the Asian side at Chalcedon (modern Kadıköy), seemingly blind to the superior location across the water. The settlement, named Byzantium after its founder, thrived on trade, fishing, and its ability to control sea traffic passing through the strait. Over the following centuries, Byzantium was fought over by Persians, Athenians, Spartans, and eventually became part of the Roman Empire in 73 AD. The ancient hippodrome, whose remains can still be seen in Sultanahmet Square, dates from this Roman period.
Constantinople: Capital of the Roman Empire (330 – 1453)
The city's destiny changed forever in 330 AD when Roman Emperor Constantine I chose Byzantium as his new capital, renaming it Constantinople — the City of Constantine. He built massive city walls, grand public buildings, churches, and forums, transforming the modest town into one of the ancient world's greatest cities. Under Emperor Justinian I in the 6th century, Constantinople reached its first golden age. Justinian built the Hagia Sophia in just five years (532-537), creating what would remain the world's largest cathedral for nearly a thousand years. He also codified Roman law and expanded the empire's territory. The Theodosian Walls, built in the 5th century, protected the city for over a thousand years and remain standing today as one of Istanbul's most impressive historical monuments.
The Byzantine Golden Age and the Crusades
As the western Roman Empire fell, Constantinople became the heart of the Byzantine Empire — a civilization that preserved Greek learning, Roman governance, and Christian theology for a millennium. The city became the richest and most cultured in the medieval world, home to perhaps half a million people when most European cities numbered in the thousands. Its wealth attracted enemies, however. The Fourth Crusade of 1204 brought devastation when Crusaders, originally bound for the Holy Land, instead sacked Constantinople and ruled it for 57 years, stripping its treasures and weakening the empire fatally. Though the Byzantines recaptured the city in 1261, Constantinople never fully recovered its former glory, setting the stage for the Ottoman conquest that would come two centuries later.
The Ottoman Conquest of 1453
On May 29, 1453, the 21-year-old Ottoman Sultan Mehmed II achieved what many had attempted before: the conquest of Constantinople. After a 53-day siege involving over 80,000 troops, massive cannons, and the ingenious strategy of rolling warships overland into the Golden Horn to bypass the chain barrier, the legendary walls were breached. Emperor Constantine XI died fighting on the walls, and the Byzantine Empire came to an end after 1,123 years. Mehmed, who became known as Fatih (the Conqueror), immediately proclaimed the city the new Ottoman capital. He converted the Hagia Sophia into a mosque, repopulated the city by inviting people of all religions and ethnicities, and began the transformation that would create the Istanbul we recognize today.
The Ottoman Golden Age (1453 – 1600)
Under the Ottomans, Istanbul became one of the world's largest and most cosmopolitan cities. Sultan Süleyman the Magnificent (reigned 1520-1566) presided over the empire's greatest era, commissioning the legendary architect Mimar Sinan to create masterpieces that still define Istanbul's skyline. Sinan built over 300 structures including the Süleymaniye Mosque, considered his greatest achievement, as well as the Şehzade Mosque, the Rüstem Paşa Mosque, and countless baths, bridges, and schools. The Grand Bazaar, which had been established shortly after the conquest, grew into one of the world's largest covered markets. The Topkapı Palace served as the seat of Ottoman power and the sultan's residence for nearly 400 years. The city was home to Muslim Turks, Greek Orthodox Christians, Armenian Christians, and Jews living in relative harmony.
Ottoman Decline and Modernization (1600 – 1922)
From the 17th century onward, the Ottoman Empire entered a long period of gradual decline relative to rising European powers. Istanbul reflected this transformation: the sultans moved from Topkapı Palace to new European-style palaces along the Bosphorus, including the lavish Dolmabahçe Palace built in 1856. The Tanzimat reforms of the mid-19th century brought Western-style modernization — Istanbul got its first bridge across the Golden Horn, a railway terminus (the Orient Express arrived at Sirkeci Station), modern schools, and newspapers. The Pera district (modern Beyoğlu) became a cosmopolitan center with European-style buildings, embassies, and grand hotels. World War I brought the end of the Ottoman Empire, and the Allied occupation of Istanbul from 1918-1923 marked the city's lowest point in modern history.
The Republic and Modern Istanbul (1923 – Present)
When Mustafa Kemal Atatürk founded the Republic of Turkey in 1923, he moved the capital to Ankara, and Istanbul lost its status as a seat of government for the first time in 1,600 years. However, the city remained Turkey's cultural, economic, and population center. The 20th century brought dramatic changes: the construction of the first Bosphorus Bridge in 1973 physically connected Europe and Asia for the first time. Rapid industrialization and rural migration transformed Istanbul from a city of about one million in the 1950s to a megacity of over 16 million today. Modern skyscrapers now share the skyline with Ottoman minarets and Byzantine domes, creating the visual layers that make Istanbul so visually striking from any vantage point.
Historical Sites You Can Visit Today
What makes Istanbul extraordinary for history lovers is that nearly every era has left visible, visitable traces. From the Byzantine period, you can explore the Hagia Sophia, the Basilica Cistern, the Theodosian Walls, the Church of St. Savior in Chora (Kariye Museum) with its stunning mosaics, and the Hippodrome remains in Sultanahmet. Ottoman treasures include the Topkapı Palace, the Blue Mosque, the Süleymaniye Mosque, the Grand Bazaar, and the Dolmabahçe Palace. Republican-era landmarks include Atatürk's personal effects at the Dolmabahçe and the modern museums along the Bosphorus. The Istanbul Archaeological Museums house artifacts spanning all these periods and more, including the famous Alexander Sarcophagus. Walk through Istanbul's historic neighborhoods to see how past and present coexist on every street.
Istanbul's History and Its Geography
Istanbul's history cannot be separated from its extraordinary geography. The city sits on the Bosphorus strait connecting the Black Sea to the Sea of Marmara and beyond to the Mediterranean, making it one of the most strategically important locations in world history. Control of this waterway meant control of trade between Europe and Asia, between the Mediterranean and the grain-producing regions around the Black Sea. The Golden Horn, a deep natural harbor on the European side, provided perfect shelter for navies and merchant fleets. The hilly terrain of the peninsula made it naturally defensible, enhanced by the legendary Theodosian Walls. Explore the geographic details of Istanbul to understand why this precise location was chosen by empire after empire. Check the Istanbul weather forecast to plan the best days for walking tours of these historic outdoor sites, and use the route planner to map out your historical walking routes across the city.
