The proliferation of known ‘Ecclesiastical Histories’ should be located in the Greek-Byzantine world, where a theological-political reflection on the empire, conceived as universal and providential, made inroads. Eusebius of Caesarea is unanimously considered the founder of this Christian historiographic genre, which spread in later centuries in both the East and the West. Eusebius’s Chronici canones , in fact, radically transformed the formulation of Christian Chronography and he created a new literary genre with the Historia Ecclesiastica . This author conceived a new type of history, unconventional in outlook and methodological in approach, grounded in a new religion. He established and transmitted the notion that God’s plan of salvation realises itself through the centuries.

Eusebius’s notion is characterised as a providential vision of history, devoid of free will. This is one of the key differences that would soon distinguish pagan from Christian historiography. The first was based on free judgement, which was a source of pride for ancient historians. Conversely, the other was grounded in scriptural authority. Concerning pagan historiography, Eusebius’s originality lies in the object of his history, namely, the church/ churches, which he characterises as the people or the Christian nation (ethnos ). Indeed, the very title of his work, Historia Ecclesiastica , does not refer to the church as a theological and institutional entity. In this work, the word ‘church’ seldom appears in the singular, indicating the theological notion of a universal church intended as an assembly united by faith, feeling, and institutions.