Simon Sebag Montefiore looks at Istanbul's Greek roots, its transformation into the capital of a Christian empire and reveals how clashes forced eastern and western churches apart.

Simon Sebag Montefiore explores modern Istanbul in search of the last centuries of Christian Byzantium, when the once glorious city was buffeted by enemies from both east and west.

Visiting the great mosques and palaces built by the Ottoman emperors, Simon Sebag Montefiore looks at how Istanbul became the imperial capital and Islam's most powerful city.