History of Istanbul

Istanbul developed from the Greek settlement of Byzantium into the Byzantine and Ottoman imperial capital Constantinople, then became Turkey’s largest metropolis under the name Istanbul.

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Byzantium: An ancient Greek city founded on the Bosporus, later incorporated into the Roman Empire and renamed Constantinople. Its settlement established the site and name from which Istanbul’s urban history began.
Theodosian Walls: A massive system of land walls built around Constantinople in the fifth century and repeatedly repaired. Their defenses helped the city withstand sieges for centuries.
Siege of Constantinople (1453): The Ottoman siege that ended with Mehmed II’s capture of Constantinople on 29 May 1453. The conquest ended Byzantine rule and began the city’s Ottoman imperial era.
Fall of Constantinople: The capture of Constantinople by Ottoman forces in 1453, ending the Byzantine Empire. The event reshaped political power, religious life, and population in the city.
Bosporus: A strait connecting the Black Sea and the Sea of Marmara, separating Europe from Asia. Control of this passage made the city a strategic link between continents and seas.
Golden Horn: A natural harbor inlet on the European side of Istanbul, opening into the Bosporus. Its sheltered waters supported trade and naval defense within the historic city.
Mehmed II: Ottoman sultan who captured Constantinople in 1453 and made it the empire’s capital. His rebuilding and resettlement policies directed the city’s post-conquest transformation.
Ottoman Constantinople: Constantinople as an Ottoman imperial capital from its conquest in 1453 until the empire’s end. Its mosques, markets, and institutions define a major layer of Istanbul’s urban inheritance.
Constantine the Great: Roman emperor who reunified the empire and founded Constantinople as a new imperial capital in 330. His refoundation transformed the former Greek city into an imperial center.
Hagia Sophia: A monumental Istanbul building completed as a Byzantine cathedral in 537 and later used as a mosque and museum. Its changing functions reflect successive imperial and religious regimes.