As one might expect, Istanbul has a colorful and eventful history.

This story starts way back in the 7th century B.C., when the Megara king Byzas and his people settled into the Asian side.  Thus, the colony known as Byzantium was established.  King Byzas selected this place based on the statement of an oracle of Delphi.  The oracle specified that he should establish the city in front of the “land of the blind”.
constantine the great
Alexander the Great added this city to his empire during the 4th century B.C.  And in the 2nd century B.C. Septimus Severus (the Roman Emperor then) took the city in the name of the Roman Empire.   Severus renamed it in honor of his son – Augusta Antonina.  This city was catapulted into its position of power and influence during the reign of Constantine the Great.  He decided to rebuild the city upon seven hills and made it the capital of the Roman Empire.  He also named it after himself – Constantinople.  For around a thousand years, Constantinople enjoyed the prestige of being the last outpost of the Roman (and then the Byzantine) empire.

justinianOther emperors following Constantine started the task of filling the city with cultural and historic treasures.  However, because of riots during Justinian I’s reign, some of these were destroyed.  But the city managed to rise magnificently from the ashes.  After these destructive riots, more structures where built or rebuilt.  A prime example of this would be the Hagia Sophia.

Because of Istanbul’s desirable position, it has become witness to many a struggle for control and possession.  Siege after siege and war after war was fought within the city.  Arabs, “Barbarians” and Crusaders fought for control until the city was sacked and destroyed during the Fourth Crusade.
mehmet iiThen in 1453 Sultan Mehmet II gained control of Constantinople after a siege of 53 days, thus ending the Middle Ages.  This started the reign of the Ottoman Turks.  During this period, mosques and public buildings were built, many of which were built by Sinan (a renowned architect) and are fine examples of Ottoman architecture, such as the Grand Bazaar, the Fatih Mosque (which was built on the ruins of the Church of the Holy Apostles) and the Topkapi Palace.  Istanbul saw the height of Ottoman architectural and artistic achievement during the reign of Suleiman the Magnificent, especially when it comes to calligraphy and ceramic art.
It was only during the First World War that Istanbul saw the end of the Ottoman rule.  Ataturk led the city into the next era.  Thus, the city witnessed the beginning and establishment of the Republic of Turkey in 1923 after the War of Independence.  Ataturk then moved the capital of Turkey to Ankara.  However, the city of Istanbul continued to develop, as buildings, parks and squares were constructed all throughout.

Post 2nd World War, Turkey experienced a lot of political upheavals, until the creation of the 3rd Republic and Modern Turkey.