Title: Byzantium
Content:  the capital of the Byzantine Empire, which decorated the city with numerous monuments, some still standing today. With its strategic position, Constantinople controlled the major trade routes between Asia and Europe, as well as the passage from the Mediterranean Sea to the Black Sea. On May 29, 1453, the city fell to the Ottoman Turks, and again became the capital of a powerful state, the Ottoman Empire. The Turks called the city "Istanbul" (although it was not officially renamed until 1930); the name derives from "eis-ten-polin" (Greek: "to-the-city"). To this day it remains the largest and most populous city in Turkey, although Ankara is now the national capital.
Title: Constantinople
Content:  Constantinople ( Kōnstantinoupolis; Constantinopolis; ) was the capital of the Roman/Byzantine Empire (330–1204 and 1261–1453), the Latin Empire (1204–1261) and the Ottoman Empire (1453–1922). The capital then moved to Ankara. Officially renamed as Istanbul in 1930, the city is today the largest city and financial centre of the Republic of Turkey (1923–present). In 324, the ancient city of Byzantium was renamed “New Rome” and declared the new capital of the Roman Empire by Emperor Constantine the Great, after whom it was renamed, and dedicated on 11 May 330. Constantinople is generally considered to be the center and the "cradle of Orthodox Christian civilization". 
Title: Outline of the Byzantine Empire
Content: Constantinople (capital) ; Thessalonika 
Title: Byzantium
Content:  Byzantium or Byzantion  was an ancient Greek city in classical antiquity that became known as Constantinople in late antiquity and Istanbul today. The Greek name Byzantion and its Latinization Byzantium continued to be used as a name of Constantinople sporadically and to varying degrees during the thousand year existence of the Byzantine Empire. Byzantium was colonized by the Greeks from Megara in 657 BC, and remained primarily Greek-speaking until its conquest by the Ottoman Empire in AD 1453.
Title: Byzantine Anatolia
Content:  Byzantium had long been considered of strategic importance, guarding the access from the Black Sea to the Aegean. Various emperors had either fortified or dismantled its fortifications depending on which power was using it and for what. Byzantium featured in Constantine's last war against Licinius in which Constantine had besieged the city, and after the war was over he further investigated its potential. He set about renewing the city almost immediately, inaugurating it in 330. This is a year sometimes picked as the beginning of the Byzantine Empire. The new capital was to be distinguished from the old by being simultaneously Christian and Greek (although was initially mainly Latin speaking like its Balkan hinterland) and a centre of culture. However the empire split again on his death, only to be reunited again by Theodosius I (379–395).
Title: Cities in the Byzantine Empire
Content:  In the Byzantine Empire, cities were centers of economic and cultural life. A significant part of the cities (there were more than 900 of them by the 6th century) were founded during the period of Greek and Roman antiquity. The largest of them were Constantinople, Alexandria and Antioch, with a population of several hundred thousand people. Large provincial centers had a population of up to 50,000. Although the spread of Christianity negatively affected urban institutions, in general, late antique cities continued to develop continuously. Byzantium remained an empire of cities, although the urban space had changed a lot. If the Greco-Roman city was a place of pagan worship and sports events, theatrical performances and chariot races, the residence of officials and judges, then the Byzantine city was primarily a religious center where the bishop's residence was located.
Title: Byzantine Empire
Content:  The Byzantine Empire, also referred to as the Eastern Roman Empire or Byzantium, was the continuation of the Roman Empire in its eastern provinces during Late Antiquity and the Middle Ages, when its capital city was Constantinople. It survived the fragmentation and fall of the Western Roman Empire in the 5th century AD and continued to exist for an additional thousand years until it fell to the Ottoman Empire in 1453. During most of its existence, the empire was the most powerful economic, cultural, and military force in Europe. "Byzantine Empire" is a term created after the end of the realm; its citizens continued to refer to their empire simply 
Title: Succession to the Byzantine Empire
Content:  The Byzantine Empire was the medieval continuation of the ancient Roman Empire, with its capital having been transferred from Rome to Constantinople in the 4th century by Rome's first Christian emperor, Constantine the Great. The term "Byzantine" is an historiographical exonym: the people in the empire continually self-identified as "Romans" and referred to their empire as the "Roman Empire" or "Romania" (meaning "land of the Romans") throughout its existence. As the successor of the ancient Roman emperors, the power of the Byzantine emperor (officially titled the "Emperor of the Romans"; in later times the "Emperor and Autocrat of the Romans") was nearly 
Title: Economic history of Greece and the Greek world
Content:  The Byzantine economy was the economy of the Byzantine Empire which lasted from Constantine's foundation of Nova Roma (Constantinople) as the capital of a Hellenized, truly 'Graeco-Roman' Empire in 330 to 1453. Throughout its history it employed vast numbers of people in huge industries, particularly in the Capital and Thessaloniki (the second city of the empire), in all manner of trades, such as the silk industry.
Title: Middle Eastern empires
Content:   Constantinople, situated on the Bosporus Straits at the mouth of the Black Sea, became the capital of the Roman Empire in 330 CE after Constantine the Great, the first Christian emperor, refounded the city of Byzantium. Although the city was called Constantinople until its fall, the Eastern Roman Empire became known by the classical name of Byzantium, and often the city was called by its old name as well. The city's status as residents of the Eastern Roman Emperor made it into the premier city in all of the Eastern Roman colonies in the Balkans, Syria, Jordan, Israel, Lebanon, Cyprus, Egypt, 

Question: What is the capital of Byzantine Empire?
Answer: Constantinople.
Istanbul.