Capital of the Eastern Roman (Byzantine) Empire (395 - 1453)

Upon the death of Theodosius in 395 AD the empire was partitioned into East and West, and Constantinople became capital of the Eastern Roman Empire, subsequently known as the Byzantine Empire. The first Byzantine emperor was Arcadius (395-408). The short reign of Arcadius was followed by the long one of Theodosius II (408-450), who in 439 constructed new additions to the three sets of walls, closing up all weak points in the land and sea walls.

The first synagogue built in Istanbul was located in the district of Bakırcılar, and was converted into a church by Theodosius II in 450. In the sixteenth century there were over thirty synagogues in Istanbul.

The great cistern built in the sixth century by Justinian I (527-565) to supply the palace with water became known as the Basilica Cistern because the commercial basilica stood on top of it. Two of the 336 columns in the cistern stand upon carved heads of Medusa taken from earlier buildings.

Haghia Sophia had been burned down twice during insurrections and was rebuilt by Justinian in 537. Various stories about the church were current aınong the people of Istanbul. One of these related that during mass one day the Emperor Justinian dropped the holy bread in his hand. Before he could bend down to pick it up, a bee seized the bread and and flew off with it. The emperor sent messengers to bee keepers throughout the empire telling them to look out for this bread in their hives, and offering a reward for whoever found it. A few days later a bee keeper came to the capital with an unusually shaped honey comb thought to have resulted from the effects of the holy bread. Justinian decided to construct a şplendid church on the same plan as the honey comb. Anthemius of Tralles and Isidor of Miletus were appointed architects of the church, which rose up in its full splendour. The church was renovated and restored on numerous occasions over the next fourteen centuries, the last major changes being carried out by the Swiss Fossati brothers at the request of Sultan Abdülmecid in 1847-1849.

Another Byzantine Church, the Chora, contains what are thought by many to be the most spectacular examples of Byzantine frescos and mosaics depicting biblical scenes. This church took its present form in the fourteenth century; and was converted into a mosque by Sultan Bayezid II (1481-1512).

Byzantine Constantinople never recovered from the destruction and plunder of the Fourth Cn.ısaders, who occupied the city and established a Latin Empire there. The Byzantine Empire regained control of Constantinople in 1261, but even an ambitious building programme could not restore the city to its former splendour and prosperity. The population, which had once been 500,000, steadily declined to 50,000. Production levels diminished and famine broke out. A thousand year-old chapter of history was drawing to an end, and the city was on the brink of a new era as the Ottoman Turks gradually advanced through Asia Minor and the Balkan peninsula.