How and why did the late ancient world come to be distinguished from the 'classical' civilization? From 150 to 750 AD, the most deeply rooted ancient institutions disappeared forever. In 476, the Roman Empire ceased to exist in Western Europe. In 655, the Persian Empire vanished from the Near East. Peter Brown does not narrate a melancholic story of 'decline and fall', but soberly examines the rearrangement of ancient borders and the emergence of critical new phenomena that marked the era, such as the dominance of Christianity in Europe and Islam in the Middle East. Pioneering in the 1970s, now a classic, this vivid essay highlighted the uniqueness of a neglected historical period, shifting the focus from Western Europe to the Eastern Mediterranean. Surveying six hundred years of political, social, and cultural changes, it attempts to answer a crucial question of world history: how did the homogeneous Mediterranean world of 200 AD end up divided into three alienated and competitive entities, the Catholic West, Byzantium, and Islam? A development whose long-term consequences we still experience today, at the end of the second millennium. (From the presentation of the edition) This book was written around 1970, not as a 'definitive' manual but, clearly, as an essay. I wanted to convey to the average reader the sense of richness and allure of a once neglected era, now known as 'Late Antiquity'. As an essay, the book had clearly limited boundaries: the text and the accompanying bibliography covered certain topics while others were not addressed at all. It reflected, with genuine enthusiasm, a specific moment in the evolution of late antiquity studies in Europe, and in England in particular. It focused on the cultural and religious history of the period and the social changes that seemed to me, at the time of writing, to offer a framework for interpreting the impressive fermentations of the era. It directed the reader's attention beyond the areas that had, until then, dominated the scene of most narratives of the 'decline and fall' of the Roman Empire - in other words, beyond Western Europe and the Western barbarian world; and it emphasized, by preference, the eastern shores of the Mediterranean and the Middle East. What has changed, both within me and in the educated world as a whole, is not easy to summarize. But it must be kept in mind by those consulting the bibliography. One thing is certain: most of the books I added are dreams that came true. We greatly needed them in 1970. They are encouraging evidence of the development of studies on the period of late antiquity over the last two decades... These books do not merely correct - or complement - the present essay. They bring good news. They now encourage other scholars to once again embrace, after nearly twenty years, the challenge of an eternally fascinating era, knowing much more than I did then. [Excerpt from the introduction text of the edition]