Here we present a part of the «Introduction» from the book «Historical Dictionary of Byzantium», by John H. Rosser.
“No state ever existed that called itself either ‘Byzantium’ or the ‘Byzantine Empire’. These are modern, conventional terms for the Roman Empire from 324-1453: from the foundation of Constantinople (formerly called Byzantium) to the conquest of the city by the Ottoman Turks in 1453. The ‘Byzantines’ always called themselves Romans (romaioi), and referred to their emperor as Emperor of the Romans (basileon ton Rhomaion). After 324 the orientation of the Roman Empire became more eastern, partly because Constantinople (also called New Rome; modern Istanbul), founded by Constantine I the Great, lay in the East. From the seventh century onward the heartland of Byzantium lay in Asia Minor, in what now comprises modern Turkey, and Byzantine possessions in the West were reduced to southern Italy. One can understand why some have called it the ‘Eastern Roman Empire’. What is important to realize is that ‘Byzantium’ refers to the Roman state after 324.
Byzantium was a Christian empire. To understand how this happened, one must turn again to Constantine I, who himself became a Christian in ca. 312, the first Roman emperor to do so. Constantine actively supported the church, and participated in church affairs, including the Council of Nicea in 325, which declared Arianism a heresy. The emperor’s role in the church established the emperor as God’s viceroy on earth, the 13th apostle, as it were. Constantine’s program of church construction laid the foundations for Christian architecture. Subsequently, Byzantine art developed as a religious art. Thus, not only did the Roman Empire change by virtue of its new capital and eastern orientation but also it became the chief supporter of the Christian church.
Byzantium was gradually transformed by these changes. The perception of Byzantium as lacking vitality, as exotically ritualized and conservative in its court and administration, and as perpetually in decline, even corrupt, reflects a western medieval viewpoint that persisted into modern times. The truth is quite the opposite. Byzantium showed a vitality unmatched by any medieval state. Rather than perpetual decline, one finds periodic renewal, even after Byzantium was destroyed by the Fourth Crusade in 1204. That it was the only medieval empire of long duration is proof of its vitality, of its ability to transform itself in the face of serious external threats.”
Research-Selection: Anastasius Philoponus