Istanbul (, or ; ), historically known as Constantinople and Byzantium, is the most populous city in Turkey and the country's economic, cultural, and historic center. Istanbul is a transcontinental city in Eurasia, straddling the Bosphorus strait (which separates Europe and Asia) between the Sea of Marmara and the Black Sea. Its commercial and historical center lies on the European side and about a third of its population lives on the Asian side. The city is the administrative center of the Istanbul Metropolitan Municipality ( with Istanbul Province), both hosting a population of around 14.7 million residents. Istanbul is one of the world's most populous cities and ranks as the world's 7th-largest city proper and the largest European city. 

Founded under the name of "Byzantion" (Βυζάντιον) on the Sarayburnu promontory around 660 BCE, the city developed to become one of the most significant in history. After its reestablishment as "Constantinople" in 330 CE, it served as an imperial capital for almost 16 centuries, during the Roman and Byzantine (330–1204 and 1261–1453), the Latin (1204–1261), and the Ottoman (1453–1922) empires. It was instrumental in the advancement of Christianity during Roman and Byzantine times, before the Ottomans conquered the city in 1453 and transformed it into an Islamic stronghold and the seat of the Ottoman Caliphate.
what is the population of Istanbul?
what name was it founded under?
in what year?
what is one of the historical names for it?
how many continents does it straddle?
which two?
how many centuries has it been an imperial capital?
how does its population rank in comparison to other cities of the world?
about how many people live on the european side?
is it the largest city in Europe?
when did Ottomans conquer the city?
what become the dominant religion there?
was it always?
what other religion was it instrumental to?
during what period?
what years did that span?
when was it reestablished as Constantinople?
around 14.7 million
around 14.7 million r
"Byzantion"
ounded under the name of "Byzantion"
around 660 BCE
around 660 BCE
Constantinople
 historically known as Constantinople
Two
straddling the Bosphorus strait (which separates Europe and Asia)
Europe and Asia
Europe and Asia
almost 16
 imperial capital for almost 16 centuries
the 7th-largest city proper
 world's 7th-largest city proper 
about two thirds
European side and about a third of its population lives on the Asian side
Yes
he largest European city. 
1453
 Ottomans conquered the city in 1453
Islam
transformed it into an Islamic 
No
 It was instrumental in the advancement of Christianity 
Christianity
instrumental in the advancement of Christianity
the Roman and Byzantine times
Christianity during Roman and Byzantine times
33-1453 in total
 (330–1204 and 1261–1453), the Latin (1204–1261
330
Constantinople" in 330