... The reformed Roman empire of Diocletian and Constantine was the most formidably governed state ever created in the ancient world. It survived largely intact in its eastern regions until 640. The consolidation of the Iranian territories under the Sassanian King of Kings involved a similar, if less clearly documented achievement. After a period of civil wars, the Islamic caliphate emerged, under the Abbasid dynasty at Baghdad, to form what has rightly been called the last great empire of antiquity. As a result, the populations of western Eurasia (even those of western Europe) could look back, in the year 800, to find their horizon blocked by the massive outlines of great empires, frequently overhauled since 250 yet still irreplaceable.

But there was more to it than that. Today, as Jews, Zoroastrians, Christians, and Muslims, millions of persons are the direct heirs of religions either born or refashioned in late antiquity. Some religions took the form in which they are still recognizable–as was the case with the Jews–within communities bounded by the Roman and Sassanian empires. Others grasped the fact of empire with spectacular results. Zoroastrians look back to the age of the Sassanians as the time of the restoration of their orthodoxy and of the formation of their religious literature. The Christians embraced with zeal the Christian Roman Empire of Constantine and his successors. The Muslims created rapidly, from the remnants of the Roman and the Sassanian states, an empire of their own.

This, very briefly, is what we mean when we talk of "late antiquity." ... [T]he time has come for scholars, students, and the educated public in general to treat the period between around 250 and 800 as a distinctive and quite decisive period of history that stands on its own. It is not, as it once was for Edward Gibbon, a subject of obsessive fascination only as the story of the unraveling of a once glorious and "higher" state of civilization. It was not a period of irrevocable Decline and Fall; nor was it merely a violent and hurried prelude to better things. It cannot be treated as a corpse to be dragged quickly offstage so that the next great act of the drama of the Middle Ages should begin--with the emergence of Catholic Europe and the creation of the Arabic civilization associated with the golden age of medieval Islam.

Not only did late antiquity last for over half a millennium; much of what was created in that period still runs in our veins. It is, for instance, from late antiquity, and not from any earlier period of Roman history, that we have inherited the codifications of Roman law that are the root of the judicial systems of so many states in Europe and the Americas. The forms of Judaism associated with the emergence of the rabbinate and the codification of the Talmud emerged from late antique Roman Palestine and from the distinctive society of Sassanian Mesopotamia. The basic structures and dogmatic formulations of the Christian church, both in Latin Catholicism and in the many forms of eastern Christianity, came from this time, as did the first, triumphant expression of the Muslim faith. Even our access to the earlier classics of the ancient world, in Latin and Greek, was made possible only through the copying activities of late antique Christians and their early medieval successors, locked in an endless, unresolved dialogue with their own pagan past.