Fans of Roman architecture are in for a treat on BBC iPlayer, as historian and author Simon Sebag Montefiore explores Istanbul and its collage of ancient architecture, dating from the Greeks onwards.

Examples of some of the most majestic Roman architecture are examined, including Emperor Justinian’s simply fabulous subterranean water system built by Roman slaves to make the city of Byzantium siege proof.

Emperor Constantine’s vast hippodrome leading to his palace may now be full of tourists,  but the huge pylons he imported stand proud against the skyline, helping bring Byzantium to the fore and making it the new imperial capital of the Roman Empire.

Sebag Montefiore shows how a simple Greek fishing port became the beating heart of the Roman Empire, facing up to Persia in the east, Rome’s chief enemy – and eventually became a rival to Rome.

It is thought Constantine’s conversion to Christianity thirty years before he happened on Byzantium partly explains the rise of the city – making Constantine  determined to create a purely Christian capital.

As if the programme were not exciting enough, we go in search of Constantine’s sarcophagus – and try and solve the mystery of the thirteenth apostle of Jesus and a possible heresy.

The challenge to Rome Constantinople presented is also explored, as well as the myth of Emperor Justinian and Empress Theodora and the sixth century Hagia Sophia – and how blood ended up buried beneath the streets of the city.

Warning this episode contains some details of torture which some might find upsetting.

Byzantium: A Tale of Three Cities is available on BBC iPlayer.

The second episode is on BBC4 on 16 February.

Buon viaggio!

All images Creative Commons licence.