James J. O'Donnell:  It was on the 24th of August, in the year 410 of the common era, that the unthinkable came to pass. A guerrilla army, led by a renegade Roman general named Alaric, who had been brought up in a German-speaking community outside the actual boundaries of the Roman empire, ended years of threats and intimidation by invading the city of Rome itself. For three days they remained, destroying, looting, and killing. The exact loss of life was never known and may have been less than fears of the moment said it was, but the experience was a shattering one nonetheless. It had been 800 years since the last such defeat of the city, 800 years in which Rome had grown to be the greatest city in the world, the envy of the nations, the model for what a great city was like.

The shock was felt throughout the Roman world. In far-off Bethlehem, the scholar and monk Jerome, so prolific that one might think of him as the Stephen King of his time, could not work.

Here are his words: "And I was stunned and stupefied, so much so that I couldn't think about anything else day and night. I felt as if I were being held hostage myself and couldn't even open my mouth until I knew for sure what had happened. Hanging there, caught between hope and despair, I was torturing myself with the thought of what others were suffering. But after the brightest light of all the lands was extinguished — after the head of the whole Roman empire was lopped off — to speak truly, after the whole world had perished in a single city: I fell silent and was humbled, and I kept my silence and my sorrow was renewed. My heart grew warm within me and fire blazed up in my thoughts ..."

I have been reading and thinking about the events of 410 for over thirty years, but never with the intensity and compassion that I have known since that other ghastly day last September. So forgive me: I am a historian, and I have a story to tell this afternoon. History of this kind offers us a way to think about our world — but it offers no obvious or simple answers to our questions. I hope you will give me leave to provoke you for a while.

Roman government's response to the crisis was military and ineffective. The Roman emperor had years earlier moved his western court to the northern Italian city of Ravenna, protected by surrounding marshes and with a sea-lane for escape, but he sent his troops to pursue the enemy, then negotiate with him, then pursue him some more. From the official perspective, the issue was simple: barbarism versus civilization. The renegade general and his followers were demonized, pursued, and feared. Within a few years, they had migrated to what is now modern Spain and settled there, establishing a regime that thrived independent of Rome for three hundred years - until the Islamic invasions.

The years that followed were marked by a series of such migrations. The Spanish kingdom we call Visigothic, after the ancestral people of their generals. Within the century, Roman Africa fell into the hands of the Vandals from northern Europe, Roman Gaul into the hands of the Franks (who would give their country a name it still holds), and Italy itself became the homeland of the Ostrogoths. Barbarism had triumphed. To be sure, Roman armies in this period were recruited heavily from among the same peoples, and it happened more than once in the fifth century that you could not tell the Romans on a given battlefield without a scorecard - on one occasion two different contenders for the imperial throne itself fought each other through proxy armies led respectively by Vandals and by Visigoths.

But on the ground, it is far from clear that these developments constituted a defeat for civilization. Within a decade of the sack of Rome, Alaric's successor was being quoted as saying that in his youth he had thought to overthrow the Roman empire and replace it with a Gothic one, but now in power he saw that his people needed the law and structure of Roman civilization to have peace and prosperity for themselves. All of those "barbarian" kingdoms would soon rewrite the Roman law codes for local use and practice, in eloquent testimony to the power of the greatest of Roman civil achievements.

Roman government persisted in demonizing the barbarian, and the politics of the fifth and sixth centuries persisted in seeing the challenges of the age as military and technological. They could not have known or heard the lesson of a famous line from the modern French poet Paul Valery: "Seeing is forgetting the name of the thing one sees." The Romans of that age knew exactly what they were seeing - and it made them blind to the reality around them.

And so the long dance of Roman armies and barbarian ones played out, and in the end, Rome was the loser. Preoccupation with barbarians took attention away from another more threatening military frontier, the one shared with Persia, and gradually Roman resolve and strength were worn away there. When Islam arose in the seventh century, the remaining Roman power, headquartered at Constantinople (modern Istanbul) was unable to mount more than a token resistance.

But the final irony is important to grasp. You may have visited modern Rome or seen pictures of its ancient ruins, and you may be thinking that the events of 410 of which I spoke earlier can explain what you have seen. Not so.

The greatest destruction visited upon the city of Rome, the depredations that left most of the city a prey to malaria and a home to oxen and owls for a thousand years, came not from barbarian invaders but Roman ones. In the mid-sixth century, the reigning emperor at Constantinople, preoccupied with his vision of barbarism versus civilization, sent his own mercenary army (containing, to be sure, a good many fighters of non Roman stock) to recapture Italy for the empire. The fifteen years of war that followed were responsible for the destruction of much of the physical fabric of Rome, and responsible as well for shattering the political and social unity of the peninsula that had been built up laboriously through many centuries. From the sixth century to the nineteenth, there was no Italy, only a peninsula divided among pieces of other people's property. That disarray was the result not of barbarism, but of self-styled civilization run amok.

Could it have been otherwise? Was there an alternate future in the aftermath of the sack of Rome? Choices in history are hard to see as we live the history, but perhaps a little easier to see from a distance.

Some of the refugees from the events of August 410 landed up in a grimy seaport city in Africa, then called Hippo Regius, today the city of Annaba in Algeria. A backwater by any standards, it owed its standing to its harbor, through which the grain and olive supply of the province of Numidia - think of it as the Roman Nebraska - came down to the sea for shipment to the capital city. It was a natural place for wealthy refugees to make landfall, and a fair number of them indeed owned the great Numidian estates in the breadbasket of empire.

The leading figure of the city of Hippo in those days was the Christian bishop, Aurelius Augustinus, known to us as Augustine or Augustine. He was at this period a minor provincial figure, known within a limited circle for some of his theological writing (including the Confessions), but deeply engaged in local politics and church politics, fighting a relentless battle against other sects of his own religion. An indefatigable social climber, he made his way among the wealthy refugees, and found there disturbing ideas in circulation. Perhaps, it was being said, the sack of Rome came from a religious failure. For centuries we worshipped the old gods in the old ways and they protected the city; now in the last century we have given allegiance to a puzzling kind of new age religion — Christianity— , and a fat lot of good it has done us.

Augustine could not stand such defeatism, and so began to write a book. His motives were self-interested and polemical, but the book quickly transcended its moment. Over the next two decades, starting from that moment of crisis and doubt, Augustine elaborated his view of human society and human history in the twenty two books of his work entitled the City of God.

The book was finished long after the sack of Rome had faded from the newspapers and before the next wave of invasions trapped Augustine in his own city, where he died in 430. What marks the book is its dramatic and inclusive vision of a society that transcends the divisions of that particular time. This is not the place to outline its contents or its theology, but it should be easy enough for you to imagine the perspective, so familiar is it to moderns. The organizing principle of human history for Augustine was not membership in a given nation or state, but participation in a society that was notionally worldwide in its scope and eternal in its duration.

My point is not to test how much of that particular vision may still make sense today, but to emphasize its visionary quality. In a world where governments and soldiers emphasized division, Augustine found a way to emphasize inclusion. His criterion of inclusion was less than absolutely world-wide, of course, depending as it did on the Christian religion. But all the barbarians whom men feared in those days, all of them, were Christians of one stripe or another. To speak of a Christian vision of society, then, was to find a way to talk about humankind that embraced potentially all the warring and suspicious parties of the time.

Emperors, generals, and armies were little influenced by African bishops and their books. But the grassroots organization of Christianity - in large measure sponsored by government suppression of their opponents - had spread far enough and wide enough in those days to make a difference. When the supposedly "barbarian" communities of the western Mediterranean made their peace and settled down in the fifth and sixth centuries, bishops and monks were the community leaders who made sense of the world, along lines not very different from what Augustine laid out. If you want a hero for this story, you want perhaps not Augustine but Theoderic. Theoderic was the Ostrogothic king of Italy from 490 to 526 CE, a time that contemporaries spoke of as a golden age, when you could leave your money lying by the side of the road at night and find it there untouched in the morning - an exaggeration perhaps, but an exaggeration that speaks volumes for the social order that underlay it. Under his leadership, sects of Christians who engaged in mutual persecution in other lands lived side by side in remarkable harmony. You can visit Theoderic's massive tomb today in Ravenna, or read his words on at least one Penn website: "civilitas", the Latin word for something like "civility" or even "civilization", was his favorite theme. Not bad for a supposed "barbarian".

But if books are mostly ineffective as instruments of social change in the short term, they can, however, be persuasive in the long run. It can and should be argued and understood that the peculiarly European vision of humankind that gives birth eventually to the university tradition we embody today in our robes and rituals and to a whole series of widening circles of inclusive imagination of human society goes back to this age. The sense of community that binds together western nations today, that gave rise to such diverse organizations as the Catholic Church, the European Union, and World Cup football take their origins in that late antique vision of a society whose inclusiveness transcends old and seemingly obvious divisions.

But what are originally visions of inclusiveness have a way of exhausting themselves. The Roman empire had lost its ability to embrace new peoples by the time of which I have been speaking, and it is only too clear that in our time the traditional religions of the book, though their wisest practitioners speak well and act fairly, have lost much of their persuasive inclusiveness. It is indeed precisely the mode of their claims at universality that puts them most in conflict with each other.

The challenges today are thus obvious and many, but the opportunity is great as well. Few would have thought in the first half of the twentieth century that France and Germany could ever live so much at peace as they do now, and at the height of the Pacific war, it was unthinkable that Japan and the United States could ever become the allies they have now become. Our current strife may find its own comparable resolution, if we are wise and generous and visionary. Whether the vision we need comes from theologians or politicians or holders of McDonald's franchises is very much in doubt. I take some encouragement from a ragtag band of aging hippies and young computer scientists who are planning to build a clock.

The clock they build - and the library that goes with it - will be designed to live for 10,000 years: the clock of the long now, they call it, and there is a mountain in Nevada under which they plan to build it. They are already preparing for the future in ingenious and whimsical ways. They would report today's date, for example, as May 13, in the year 02002 - the initial zero being their way of reminding us to begin preparing for the inevitable Y10K crisis, hurtling towards us in a mere 7,998 years. Their mission is to encourage all who hear them to think beyond this year, this decade, or this lifetime, to remember that we live in and share responsibility for a very long future. To look out to that future is to take a deep breath and to find a place for ourselves in a narrative in which our concerns are not so paramount as they inevitably must be on a day like today.

You here may not want to be reminded of this, but very soon now, you graduates will begin bringing children into the world, children some of whom will live to see the year 2100. That's already a "now" long enough to give pause. Those children will see a world that is surely warmer and more crowded than this one. How else will it seem? That is for us, and for you, to determine, and that will be the real test of the value of what you and we have done here these last four years. Have we taught you to think in the long now? Have we taught you to forget the name of the thing you see, to forget what you think you know and see what is? Have we taught you to promote civility, to build civilization among peoples, rather than merely to oppose barbarism?

I hope we have . . .