In the last programme in the series, John Romer tells how the Byzantium empire finally crumbled. Already weakened by the ravages of rogue Crusaders it succumbed to the invasion of the Ottoman empire of Turkey and the Christian centre of the world became the Islamic city of Istanbul. The scattered refugees took their art and culture worldwide, including Florence, Rome and even Romania to give the world a lasting artistic and cultural legacy that is the link between ancient Rome and Greece and the modern world.

John Romer continues his exploration of the Byzantine empire by tracing the extent of its influence abroad. He shows that the desire of its ruler to spread the word of Christianity was not just evangelical but was also a method of subduing Constantinople's potentially dangerous neighbours. By the Middle Ages, Byzantium's influence had spread throughout Europe, but in 1204 the Venetians persuaded an army of Crusaders to divert from Palestine to Constantinople. The city was decimated, the Crusaders took control and for the next fifty years systematically looted it. In 1260 the Crusaders finally left, taking what loot remained with them, leaving what was a wrecked city.

In the opening film of this series on the Byzantine empire, John Romer traces the origins and growth of Byzantium, which under the aegis of Emperor Constantine developed from a small Greek town into a vast empire. The newly named Constantinople soon became a match for Rome. Romer also shows how it rapidly became known as a religious centre and as a cradle of great art and architecture.

John Romer continues his exploration of the Byzantium empire by looking at the creation of Christian art, with the face of Christ and the Virgin Mary first being portrayed. From the Scala Sancta, the oldest chapel of the popes in Rome where an icon is said to be the true face of Jesus to the border fortresses of Roman Syria, never before filmed.