In 324 CE, the Emperor Constantine made Constantinople (modern Istanbul) the
capital of the Roman Empire. The Ottoman Empire captured
Constantinople in 1453 and ruled the entire eastern Mediterranean
area for half a millennium. During this period, Turkey
represented the closest point of contact between the Muslim world
and Europe, and provided Europeans with much of their knowledge
about the East.
The power of the Ottoman Empire (and its perceived threat to the
West) crested in the sixteenth century, and entered a decline in
the eighteenth and nineteenth centuries. Various European powers
struggled for position, resulting in a series of wars: the Greek
War of Independence (1821-1829), the Crimean War
(1853-56), and the Russo-Turkish Wars (1877-78). The empire
finally fell apart after the First World War, and Turkey became a
republic in 1923.