This summary, based on Radi Dikici's "Four İstanbul" (2014-2017), covers Istanbul's history and transformations from 657 BCE through four key periods: Byzantion/Byzantium, Augusta Antonina, New Rome/Constantinople, and Ottoman Istanbul.

Istanbul's story begins with Byzantion. A major shift occurred on May 11, 330 AD, when Constantine the Great made it his capital, naming it New Rome, though it became known as Constantinople. This massive undertaking involved over 10,000 workers. Constantinople served as the capital of the Roman/Byzantine Empire for 1123 years and 18 days, until 1453.

The pivotal moment was the Ottoman conquest in 1453. After 12 previous sieges, the city fell to the Ottomans, ending the Byzantine Empire. Fatih Sultan Mehmet masterminded this victory. He also aimed to preserve the city's international character, appointing a new Greek Orthodox Patriarch and inviting fleeing Greeks to resettle. Armenian, Jewish, Italian, and Frankish communities were also welcomed. Fatih secured Galata, a wealthy Genoese trade center, guaranteeing their safety.

Fatih, after residing in the Byzantine Blachernae Palace, commissioned the new Topkapı Palace (1454-1478). In 1477, its diverse population included Muslims, Greeks, Jews, Armenians, Franks, and Roma. The city had many names, with "Istanbul" possibly deriving from the Greek "Eis teen polin" (to the city). Capitulations to foreign powers, starting with Venice in 1454, further boosted its global trade role.

Over centuries, Istanbul evolved. By the mid-17th century, power shifted from the palace to the Babıali (central government), leading to a more specialized bureaucracy.

Western cultural influence grew. In the late 18th and early 19th centuries, Western artists visited, and French culture, music, and dance became popular among the elite, with French replacing Persian as a prominent language.

The 19th century brought significant Western-influenced modernization. Sultan Mahmud II abolished the Janissary corps in 1826 (Vaka-i Hayriye), ending centuries of conflict and enabling new, Western-style military units. His reforms aimed to modernize the empire, marking a turning point for both the Ottoman Empire and the later Turkish Republic's Westernization. However, his economic reforms were less successful, leading to rising food prices and poverty.

Under Sultan Abdülmecit (1839-1861), Istanbul saw another golden age despite underlying contradictions. Innovations included steam ferries, telegraph services, and horse-drawn trams.

This period also saw the rise of Galata bankers, primarily Greek, who supported their community and contributed to the "Megalo Idea." Various foreign communities further diversified the city.

Sultan Abdülhamit II (1876-1909) faced a turbulent period.

Following WWI, Istanbul was occupied by Allied forces (British, French, Italian) from November 1918. This nearly five-year occupation was a period of humiliation, with visible foreign presence and escalating ethnic tensions, especially between Greeks and Turks. It fueled Turkish nationalism in Anatolia, led by Mustafa Kemal.

The occupation ended with Allied forces withdrawing by October 2, 1923. Turkish troops entered days later, marking a definitive end to an era.

Following the Ottoman Empire's defeat in WWI, Istanbul was occupied by Allied forces (British, French, Italian) from November 1918. This occupation, lasting four years and eleven months, was a period of significant humiliation and hardship, marked by a highly visible foreign presence and escalating ethnic tensions, particularly between Greeks and Turks. This occupation fueled Turkish nationalism in Anatolia, led by Mustafa Kemal.

The occupation of Istanbul officially ended with the withdrawal of Allied forces between August 24 and October 2, 1923.

Major Historical Periods and TransformationsThe Ottoman Conquest and RebirthLater Ottoman Transformations and WesternizationThe End of the Empire and the Republic