Nephew of a semi-literate peasant, Justinian I was one of the most fascinating of the Roman emperors. His reign marked a blossoming of Byzantine culture, and his prolific building works yielded such masterpieces as the church of Hagia Sophia, which remains the third largest church in Christendom. Although he never took part in military campaigns personally he managed to expand considerably the Eastern Roman Empire's territory. Justinian's wife Theodora, daughter of a bear keeper and former prostitute, was his partner in one of the greatest love stories in history. After her early death - in her forties - Justinian was devastated and sought oblivion in work, becoming known as the Emperor who never sleeps.