In a previous issue of The Social Contract, this writer cited at least 120 specific cases of ethnic conflict or major ethnic tension in about half the 194 sovereign countries of the world, just during the last three decades or so.(1) One key conclusion was that the United States, in encouraging the present huge levels of legal immigration from diverse cultures and at the same time making few real efforts to staunch the also huge illegal flow, is sowing the seeds of a similarly dangerous situation, which have already started to sprout. It carries a clear potential for breaking up the nation. Just as many other countries in all parts of the world have split apart when cultural and consequent political strains between different ethnic groups reached a breaking point, if the current trend continues it could easily happen here, very possibly well before this century is out.

The immigration-fueled demographic trend in the U.S. shows no signs of abating, and the ethnic-cultural mix of America has already been changed in irreversible ways with breathtaking speed - in barely over one generation, let alone the next two or three. It's a looming, mushrooming problem that the present generation and those following will be forced to deal with -- if they can. The longer it takes to come to grips with it, the greater the ultimate disaster will be.

Here we'll take a look at such problems by way of a historical overview. As there have been too many throughout history to be covered here, we'll take a number of examples to illustrate their pervasiveness from ancient through classical and medieval to modern times (prior to what we are pleased to call the "post-modern" period since the late 1960s, covered in my earlier article.) Some cultures span more than one, or even all, these eras. If situations affecting Western cultures receive more emphasis here, it is both because these are our own heritage and historical information is more readily available for them. Many non-Western examples show, however, that all types of human cultures are susceptible to problems of this sort.

In Ancient Times (c. 3000-500 BC)

Human history based on actual written records dates back little more than 5000 years or to roughly 3000 BC. Writing, first developed in the Near East a few hundred years earlier for accounting purposes, had by then become capable of recording the nuances of language. Thus writing came to be applied to more than just administrative records, as rulers began having their heroic deeds recorded to ensure their legacies after death. "History" by definition is what can be derived from written sources, with sciences such as archeology and anthropology filling in some of the gaps.

The first known non-pictorial writing was developed in the Sumerian city-states on the floodplain at the head of the Persian Gulf. (The world's first known major city, Uruk, with tens of thousands of people during the 3000s BC, was located on the lower Euphrates and followed by others including Ur, founded at its mouth on what was then the Gulf coastline). The Sumerians were probably a people of Caucasian(2) type, as were more surely those who lived in the region that included not only the Caucasus but stretched over a much larger area from the Anatolian Peninsula (Asia Minor, today's Turkey) well into present Iran. Flanking Sumeria were Caucasian hill peoples such as the Hurrians, Guti, and Kassites to the north and Elamites to the east. In the river plains upstream from Sumeria lived Semitic farmers such as Akkadians, and in the deserts to the south and west were nomadic Arabians. Far to the southwest lay Egypt, home to a Hamitic people who established the world's first extensive kingdom in about 3000 BC.

The region dominated by various Caucasian peoples was to shrink over the next two millennia as they became squeezed not only by the Semitic Amorites out of Arabia, but also by pincer pressures from two Indo-European groups: Iranians from the northeast out of Central Asia who conquered and settled much of the Iranian Plateau, and, from the west, Hittite invaders from Europe who took over the core of Asia Minor and dominated it for a thousand years. Thus were seeds of conflict between major cultural groups planted in the region. In these struggles the Caucasian peoples were the biggest losers, ultimately becoming confined to the Caucasus region itself. Today the only independent country speaking a Caucasian language is Georgia.(3)

Around 1640 BC, Egypt was successfully invaded for the first time by Semitic nomads whom Egyptians called the Hyksos ("foreign rulers") who made good use of war chariots, a new weapon that enabled them to carry all before them. Their specific origins are murky but Colin McEvedy depicts them as probably "the final upheaval of the Amorite expansion."(4) The Biblical Joseph's move into Egypt is usually ascribed to "the time of the Hyksos pharaohs, with their presumably favorable attitude to Semitic immigrants."(5)

The Iranian eruption from Central Asia was far from over. During the 1600s and 1500s, beside continuing movements into the Near East and Fertile Crescent, other Iranians moved east into the Tarim Basin, making China their neighbor. (To forestall these and later nomads the Chinese were prompted to build a series of earth barriers, forerunners of the Great Wall.) And in an epoch-making invasion the chariot-assisted Aryan nomads swarmed southeastward into India, which they dominated sufficiently to ensure that most languages of North India today are of the Indo-European group.(6)

Shortly after 1200 BC an apparent confederation of roving barbarian groups whom Egyptians called the "Sea Peoples" swept along the eastern Mediterranean by both land and sea. The initiators may have been of partly Dorian Greek origins but the invaders seem to have included many different groups who joined in the conquest along the way, such as Luvians of western Anatolia and Phrygians, a Thracian people, who joined in invading central Anatolia and overthrew the Hittites. The Mycenaean Greek civilization was snuffed out, and Egypt repulsed the Sea Peoples only with great difficulty. The best known single group of these invaders were called Philistines, who after being thwarted in Egypt fell back to settle in a land which came to be named for them - Palestine - where they harried the neighboring hill-dwelling Hebrews and Canaanites as well as the coastal Phoenician Canaanites. A 400-year dark age followed the various ravaging groups' passage through the Aegean, Asia Minor, and the Levant.

The period of Hebrew glory gained under David and Solomon in the 900s BC lasted barely over three quarters of a century and was followed by a split between Israel and Judah, then a series of invaders on both flanks who imposed tribute, and later total conquest by the Semitic Assyrian and Babylonian empires, both of which deported many of the Israelites and Judeans - the beginning of the Jewish Diaspora.

Meanwhile, Iranians were becoming increasingly organized and powerful. The first true Iranian empire was that of the Medes, until the Achaemenid Persians of the south under Cyrus II overthrew it around 550 BC. He and his successors Cambyses and Darius in quick succession then conquered Anatolia, Central Asia to the Jaxartes (Syr Darya) River, Babylonia, and Egypt. By 513 Persian control extended from Libya and northern Greece to the Indus River of northwestern India. The Persian Empire was easily the largest the world had yet seen and the first "cosmopolitan" one, ending the cultural isolation of several disparate civilizations. Despite being expelled from Greece shortly after Xerxes' defeat there in 480 and later temporarily losing Egypt to native rule, the Persian Empire remained essentially intact for more than two centuries.

In ancient times, since writing was used especially to commemorate the glories of kings, the internal troubles of kingdoms and empires such as ethnic dissonance tended to be given short shrift in the chronicles. Nonetheless it is a safe assumption that such problems, though under reported, were persistent. Although power struggles and wars were the order of this and other eras, the choice of enemies is often revealing. For instance, Persians found Greeks sufficiently different from their other subjects that the Empire's inclusive cosmopolitanism often was not applied to them. Although the Persians withdrew from Greece itself, many Greeks on the Persian-ruled mainland of Asia Minor were exiled to the faraway eastern reaches of the Empire to get rid of potential troublemakers. Most people of these (and later) times, of course, could not write, even had they dared to express dissent. A conspicuous example of a people who did leave extensive writings about such things were the Jews, considerable parts of their Biblical scriptures being almost a compendium of sufferings imposed by other peoples who lorded over them, the falling out of the weak among themselves, and the determination of others not to succumb to the intrigues of outsiders.

The Classical Era (c. 500 BC AD 500)

During this roughly thousand-year period the main centers of power shifted westward to Mediterranean lands. Some civilizations extended outside the geographical limits of this Europe-centered name for the era, but it is nonetheless a useful one.

For several hundred years before the "golden age" that followed the expulsion of the Persians from Greece proper, various Greek cities had been planting colonies not only along Mediterranean shores from Cyprus in the east to Iberia (Spain) in the west, but along the Black Sea coast as well. These did not constitute an empire since the separate city-states generally ran their own affairs and not infrequently warred on one other. Some of the cities founded as colonies, however, acquired what amounted to mini-empires in their own right. Syracuse,on the island of Sicily, for some time controlled the Greek-settled areas of southern Italy; Athens and Sparta fought each other for decades in four Peloponnesian wars from the mid-400s BC well into the 300s. A result of all this, however, was to spread Greek culture widely around the Mediterranean, to become a potent influence in many other developing cultures.

And not only in the Mediterranean. When Philip acceded to the throne of the northern state of Macedon in 359 BC, that once-"barbarian" region had already become thoroughly Hellenized. Philip's genius for organization and campaigning transformed Macedonia into a superpower, bringing most of Greece under effective control. He then declared war against Persia, but before he could get it under way he was murdered in 336.

His son Alexander took over and just two years later led his army across the Hellespont into Asia. The story of Alexander's campaigns through the crumbling Persian empire has been told too often to need more than the barest outline here. Alexander marched through Anatolia, Phoenicia, Egypt, then into the heart of Persia where he burned its capital, Persepolis, in 330. Pushing beyond and far into Central Asia after crossing the Hindu Kush in Afghanistan, and later bridging the Indus River, Alexander defeated a large Indian army sent against him. Although he wanted to go on into the heart of India, at this point his exhausted men refused to push farther, and he reluctantly followed the Indus south before turning back west. He had, however, in just ten years, taken control of the whole of the vast former Persian Empire and made it his own. But during a two-month return march through the deserts of Baluchistan his army met its only real defeat - not to opposing armies but to thirst and flash floods that decimated the force. Two years later, in 323 BC, Alexander fell ill and died in Babylon at only 32 years of age.

Alexander's genius was not only military but also cultural. He did not interfere with regional customs; on the contrary, he had such a show of adopting them that his men grumbled he was becoming more Asian than Greek. Although upon his death the empire split up and was divided among his generals, his legacy was to spread Greek cultural influence deep into Asia.

Greeks continued to migrate into these lands and ruled much of the huge region during the next 150 to 200 years. The most influential units were the vast Seleucid domain and the even longer-lived Ptolemaic kingdom centered in Egypt whose last monarch was Cleopatra. But another deserves special mention. In the remotest reaches of Alexander's conquests the Bactrian Greeks - after breaking away from the Seleucids in 239 BC  reached an astonishing peak of power in the 180s, when Bactria not only conquered and ruled a huge region in Central Asia, including Afghanistan and northern India to beyond Delhi, but its armies campaigned even into the lower Ganges Valley as far as the walls of Mauryan India's capital at Patna. A Greek king of its Indian half, Menander, is still enshrined as a Buddhist hero and saint for protecting Buddhists from a wave of deadly Hindu hostility that ran unchecked in the rest of India. Although most of Bactria was overrun in the 130s by Iranian nomads from the north, the last Greek principalities in the upper Indus valley did not disappear until about AD 1, three decades after the last Greek-ruled part of the Mediterranean, Cleopatra's Egypt, was absorbed by Rome.

During these centuries the main power centers were shifting toward the western Mediterranean. Although Greeks managed to establish several colonies along the coasts of present France and Spain such as Massalia (today's Marseilles), most of the early West Mediterranean cities grew out of trading settlements founded by Phoenicians. The most important of these was Carthage in present Tunisia, traditionally founded in 814 BC from Tyre. In time Carthage became master of the western Mediterranean and beyond, her ships trading as far as Britain and well down the coast of Africa. These ventures proved so profitable that Carthage was to become the richest city in the entire world.

For centuries Carthaginians waged seesaw struggles with Greeks on Sicily, neither ever gaining control of the whole island. But meanwhile a new power was emerging to the north Rome. Between 264 and 146 Carthage fought Rome in three epic Punic Wars, the greatest and bitterest conflicts fought in all antiquity. As a result of the first 25-year-long war, both sides fighting to exhaustion over Sicily, Carthage finally lost the island -- Rome gaining her first territory outside the Italian Peninsula.

Punic(7) armies were composed chiefly of hired mercenaries under Carthaginian commanders. Soon after peace was concluded those troops -- Libyans, Iberians, Balearians, Gauls, Ligurians and diverse Western Greeks -- mutinied over arrears in pay. "Lacking a common language and without the unifying force of a Carthaginian command structure, [they] fragmented into groups along ethnic lines." They cut roads and captured nearby Utica while committing horrific atrocities, forcing a major citizen mobilization to put it down. The rebellion was spurred especially by Libyans (Berbers) -- with substantial support from thousands of their "volatile blood-brothers of the interior." In the meantime, Rome made good use of the chaos by seizing Sardinia.(8)

In the years following the first war with Rome, Carthage gained more territory in Iberia (Spain) than it had lost in Sicily and Sardinia. Then, in 218 BC, Hannibal marched his army from Spain across the Alps into Italy itself (his famous thirty-seven elephants were not a factor, as nearly all died in the snows of the Alps). For fully thirteen years he led his troops up and down the Italian Peninsula almost at will, and although considerably outnumbered, decisively defeated every major Roman army sent against him. He has been called the most brilliant general in history, not excepting even Alexander.

But through a combination of Rome's dogged persistence and Carthage's lack of support and reinforcements (the leaders had determined to continue with business as usual), Hannibal was finally forced to return to Africa to fight an invading Roman force there -- where, in 202, his hastily improvised Punic forces not used to fighting together, lost a decisive battle at Zama that ended the war and Carthage's empire, leaving the Punic city with only its near hinterland in Tunisia. It left Rome with a good start on its own empire as it took Carthage's Spanish territory.

[At precisely the time Hannibal was preparing to invade Italy, far away on the opposite end of the Eurasian continent, the first Chinese empire was formed when the most powerful of its kingdoms, the Ch'in,(9) had conquered the warring feudal states of the region and brought them under tight centralized rule (219 BC). Soon after the first emperor's death the Ch'in Empire was overthrown (in 202, the year of Hannibal's defeat) and succeeded by that of the Han whose rule proved less harsh and more durable. The Chinese to this day think of themselves as their cultural heirs, calling themselves Han.]

The Third Punic War, a half-century later, was instigated by Rome. On a legal pretext Rome sent a huge force to besiege the once again prosperous and hated city. The Carthaginians defended themselves desperately in a struggle to the death for three long years -- despite being induced at the start to turn over all their weaponry in response to a false Roman peace offer. But in 146 BC the legions breached the walls and razed the city to the ground, her pitifully few survivors sold into slavery.

Thus an entire civilization was destroyed, including its whole literature as well as the spoken language itself. The only surviving writings in Punic are some terse graveyard monuments engraved in stone. In consequence, Carthage has had the singular misfortune of having had its history told entirely by its enemies, the Greeks and Romans, both of whom generally looked askance at her people and despised them as mere crafty traders while resenting their commercial success (although never averse to dealing with them). Not surprisingly, even today many scholars steeped in the Classics have acquired a bias against the Carthaginians. It is true that they practiced human sacrifice as a religious rite, though by the time of the Punic Wars that had almost died out. But a number of historians have noted that the envy, contempt and hatred displayed by Greeks and Romans toward Carthaginians and other Phoenicians marked the beginnings of Western anti-Semitism, for many of the same reasons that it was later to be directed against Jews.(10)

By the time Augustus became emperor in 27 BC the Roman superpower had expanded to encompass the entire Mediterranean, with its northern borders on the Rhine and Danube. During the first century AD Rome extended its frontiers to Britain and other peripheral areas. By the early 100s its territory had essentially stabilized.

The obverse of the question as to why the Roman Empire fell is how it lasted five hundred years. For most of that time it brought peace, prosperity and stability to the entire region, except for an occasional war on a faraway, usually eastern, frontier. It became the most universally inclusive polity the world had ever seen. In the words of the perceptive historian, Thomas Cahill, writing about these times, "The Gauls had long since become civilized Romans, and Rome offered the same Romanization to anyone who wanted it -- sometimes, as with Jews, whether they wanted it or not. Normally, though, everyone was dying to be Roman."

The issue of whether Rome fell more from internal decay or invasions by outsiders has been endlessly analyzed from both viewpoints. But whether a cause or result or both, the latter certainly played a key role in the collapse. Its background was mostly undramatic. "The barbarian migration was not perceived as a threat by Romans, simply because it was a migration -- a year-in, year-out, rag-tag migration -- and not an organized, armed assault. It had, in fact, been going on for centuries ... Sometimes the barbarians came in waves, though seldom as big as this one [Germanic Vandals and Sueves swarming across the frozen Rhine in AD 406]. More often they came in trickles as craftsmen who sought honest employment, as warriors who enlisted in the Roman legions, as tribal chieftains who paid for land, as marauders who burned and looted and sometimes raped and murdered."(11)

During Rome's last century of empire whole Germanic tribes were allowed to settle in Roman territory as federates (allies) to help guard its now thinly manned frontiers. For instance, in AD 376 the Visigoths, fleeing Hun invaders from the Asian steppes, crossed the Danube and were given sizeable lands in what is now Bulgaria by the Eastern emperor. The record of these presumed allies was, to say the least, spotty. Within twenty years, under their new leader Alaric, Visigoths were again on the move and slashed their way through Greece, where they were granted another large area to settle. But after a short pause there, they then struck northward through Dalmatia. Even the hired general that Rome sent to bar them from entering Italy, who did hold them off for a time, was of Germanic (Vandal) origin. But in 410 Alaric's forces reached Rome itself and plundered it before moving on. Later, after ravaging Spain, the Visigoths were bought off once more as federates and given sufficient good land in Aquitania (southwestern Gaul) for a rich kingdom. There they settled down for some forty years but in the 470s went on another rampage, doubling their territory in Gaul and re-invading Spain, the latter to become their core domain and remaining so for over two centuries until the Arab conquest.

The net result was that by 486 the last remnant of Rome's western empire had fallen to German tribes ranging from Franks moving south into Gaul (giving France its name), to Vandals who earlier took over the African region centered on Roman Carthage; in 455 these sent a seaborne force to sack what had been, and symbolically still was, the powerful shining light of the civilized world. Truly a bizarre twist laden with irony  Rome attacked from Carthage and vandalized ... literally.

The Medieval Era (c. 500-1500)

During medieval times most of the histories continued to be written by kings or other potentates, or rather for them by educated scribes or scholars in their employ, much as in previous eras. However, in Europe and the Near East another source of learned discourse had become influential the religious authorities. At first this mostly meant Christian - Roman Catholic in the West and Orthodox in the East, the latter based in Constantinople following the schism that developed in the late Roman Empire. The eastern part ruled by Greeks became known to history as the Byzantine Empire. It endured in one form or another for nearly a thousand years after Rome's collapse, though it had great ups and downs in the territory it controlled. (During its last two centuries Byzantine political rule was mainly confined to Constantinople and parts of Greece until the isolated city fell to the Ottoman Turks in 1453 -- although by 1000 Orthodox Christianity had spread to the Balkans, Georgia and Russia to stay.)

During these times a religious schism with consequences visible to this day split the Slavic world. By about 700 the Croats had been converted to Roman Catholicism and by 1000 so were the Czechs and Poles, while also around 700 the Serbs, in the 860s the Bulgars, and shortly before 1000 the Russians, were converted to Eastern Orthodoxy. This nipped any pan-Slavism in the bud and led to enduring antipathies between Russians and Poles as well as between Serbs and Croats.(12)

The Roman abandonment of Britain in 407, ostensibly to deal with the Germanic flood into Gaul, had left the island to the Celts. But soon the British Celts were to face raids and settlement by several Germanic tribes: Frisians, Jutes, Angles, and Saxons. Before the complete collapse of the last remnants of Rome's western empire the latter two peoples especially, out of northern Germany, had established a firm foothold in the southeast of England ("Angle Land") and were slowly pushing west. One group of British Celts in fleeing them crossed the Channel to the end of the great peninsula of northern Gaul, in numbers sufficient to give the region its present name Brittany, or "Little Britain." The Anglo-Saxons who during the 500s became dominant in much of southern Great Britain also brought their Germanic Saxon and "Anglish" tongues to the island, which were to merge and metamorphose into English.

The autocrats in Europe and the East alike, whether political or ecclesiastical or feudal, did not encourage reporting of dissent, culturally based or otherwise. In any case, those under them were rarely strong enough to consider actively challenging the status quo. While the major military conflicts involved potentates fighting over control of lands and peoples, whenever practicable they used any ethnic dissidence in lands of enemy rulers to stir up trouble against them.

In Africa and the Middle East, Arab tribes united in the name of Muhammad and barely a year after the Prophet's death in 632 burst out of Arabia, their fired-up armies carrying all before them. In quick succession they overran then-Persian-ruled Palestine, Syria, Mesopotamia, and Egypt, conquered the Sasanian Persian homeland itself and moved into Central Asia -- all in less than twenty years. They swept across North Africa and crossed to Spain in 711, where they obliterated and replaced the Visigothic kingdom. Concurrently in the east, the Arab conquest expanded farther into Central Asia; and in India, like Persians and Greeks of the preceding millennium, they reached and crossed the Indus. Religious authority in all those regions changed instantly to Islamic, with little or no distinction made between political and religious control.

In a broad sense, the overlay of cultural unity the Roman Empire had once brought to the whole Mediterranean was replaced by a wide schism between Islamic cultures dominating its southern and eastern shores, and the lands on its northern and western regions which remained mainly Christian -- as is true today, though Christians in Spain and much later the Balkan Peninsula were under Muslim rule for centuries.

In Persia, the Zoroastrian faith also fell to Islam but the Iranians, being non-Arab with a proud Persian heritage, made efforts to turn the new religion to their own ends. What began as a dynastic struggle over the succession of the caliph (a sort of combined emperor and pope in early Islam) led to the most important religious division within that faith, the "orthodox" Sunni and "renegade" Shi'a factions. While both contended in many Muslim regions, Iranians gravitated toward the Shi'a. Today, Iran is the single Muslim country with a lopsided Shi'ite majority, over 90 percent of the population.

In the following centuries Iranians staged a number of rebellions, which they justified by their own interpretations of Islamic law or doctrine. In one of the more successful of these, in 946, a Persian dynasty, the Buyid or Buwayhid, took over both Iran and Mesopotamia, and in conquering Baghdad reduced the Caliph himself to a Shi'ite vassal. Given the wide ethnic-cultural gulf between Iranians and Arabs, such developments should hardly be surprising.(13)

Shi'a Islam spawned its own renegades. An offshoot of its Ismaili branch was the Assassin sect, known for frequent use of the political technique to which it gave its name. Bernard Lewis has called it the world's first systematic long-term terror network, operating out of remote mountain castles in Iran and Syria (1090-1273). Its dedicated and fanatical operatives were feared by potentates from Egypt to Mongolia who took elaborate precautions, not always successful. Victims were usually notables in the orthodox Muslim establishment but also a few prominent Crusaders, including in 1192 the reigning Christian king of Jerusalem, Conrad of Monferrat.(14)

In the East, Tibetans had a century of power when during the latter 700s they expanded in all directions from their high plateau. On their western side they reached to the fringes of the Muslim world in Central Asia. They conquered India's Ganges Valley to the Bay of Bengal, and also made major inroads into China. In 763 they even sacked the Tang capital of Chang'an (now Xian) in the Wei River Valley, at the time the world's largest city with over a million inhabitants. By 800 the Tibetan Empire's area was greater than that of the Chinese Tang Empire itself.

In Europe, the Franks had become the most powerful group in the post-Roman West, soon after 500 subduing the rival Alemanni Germans east of them and driving the Visigoths south of the Pyrenees. Two centuries later, in 732, the Franks put an end to Arab expansion in the West at Poitiers. At their peak in the early 800s Charlemagne provided a partial respite to the Dark Ages as the Frankish Empire encompassed France, Germany, and the greater part of Italy, but in 843 the empire was divided into basically those three parts in a dynastic deal among his grandsons.

During the latter part of Charlemagne's rule and throughout the 800s the French and German realms were hard put to stave off savage Viking raids out of Norway and Denmark that harried their coasts and river valleys. The Anglo-Saxon and Celtic lands of Britain and Ireland were attacked and partly occupied for some time longer. Swedish Vikings also both raided and traded far up the rivers in Russia and established the first Russian state from Kiev. (The very name Russia derives from a Viking tribe called Rus.)

The Northmen's activity evolved from independent freebooting to organized conquest to farming settlement; but their numbers were never sufficient to swamp the existing populations, with whom they took wives, adopted Christianity, and in time became fully assimilated. The final invasion of England came from across the Channel, led by William the Bastard in 1066. (Danish Normans, i.e. Northmen, had been granted lands to settle in Normandy a century and a half earlier by the French king in return for desisting from further raiding in France.(15) By that time the Normans were speaking French, which became the official language of England for three centuries until English gradually reasserted itself, albeit with significant changes wrought by French usage.

Following the breakup of the Frankish Empire, the Holy Roman Empire was constituted in 962 and officially existed until 1806. Consisting initially of Germany and northern Italy and spilling into some French- and Slav-inhabited lands, it loomed large on the map of Europe but has been aptly described in the cliché, "neither holy nor Roman nor an empire." This "German empire" was in no way a real unification of Germany, but rather a loose confederation of large and small feudal territories ruled by independent-minded princes, dukes, counts, and also Church lands. Its map resembled a complex and changeable jigsaw puzzle, with few paying much attention to the "Imperial" authorities except when necessary -- which was not often.

A most conspicuous ethnic struggle enduring for two thousand years has seesawed between Germans and Slavs. In the first German "Drang nach Osten" ("drive toward the east") one group, the Ostrogoths, had by AD 300 penetrated southern Russia to the Black Sea and Don River and at one point even to the Volga, but before that century was out they and other German tribes were overrun by Huns from out of the Asian steppes. Later the Huns under Attila pushed to the Rhine and in one spot even touched the North Sea. (Various German groups fleeing them in turn broke across the Roman frontiers, as we have seen.) Upon Attila's death his empire quickly disintegrated and the Huns withdrew to the Black Sea steppes while the displaced German tribes finished off Rome's Western empire. To the north, the power vacuum was filled by migrating Slavs who shortly after 600 had pushed to the River Elbe and in some places beyond it - the farthest west they had ever reached - and also moved into the Balkans. The "Elbe line" was to remain a German-Slav frontier until the 1100s.

During the 1200s and 1300s the Slavic rulers of Bohemia encouraged Germans to settle in the hilly regions (Sudentenland) surrounding its central basin, in order to reap economic benefits from their industry and enterprise. While these hopes were amply fulfilled, considerable Slav territory was culturally transformed as dozens of new towns sprang up, entirely German in character.

Fast-forward some six centuries When Hitler annexed this area to his Third Reich, the sparks it set off led to World War II. Sudenten Germans avidly if understandably supported Hitler's plan, and paid a terrible price afterward. (Other areas where Germans were invited to settle in Slavic territories, and their descendants centuries later were expelled or massacred, include Polish Silesia and Pomerania and several areas in Russia.) Ethnic identity  for better or worse  can be as durable as any aspect of human nature, waiting only for a suitable opportunity to reassert itself.

Far to the east, other events were taking place that were to transform the greater part of the Asian continent and large parts of Europe as well. At various times nomadic peoples had periodically burst out of the Asian steppe grasslands - Aryans, Scyths, Sakas, Xiongnu, Kushans, Huns, Juan-juan, Avars, Pechenegs, Cumans and others who variously conquered regions from India to Iran to China to Europe. And during the 1000s, Seljuk Turks out of Central Asia similarly overran Iran, Mesopotamia, most of Arabia, and all but pushed the Byzantine Empire out of Anatolia. It brought a new ethnicity to the Near East that was ultimately to effectively change the name of that peninsula to Turkey. (At the same time it was an expansion of Islam since the Seljuks themselves had converted.) Within decades of their high-water mark in the 1090s, however, their vast empire split into several sultanates run by rival Seljuk tribes. Turks remained in regional control except for pinpricks by Crusaders in the Levant.

All this was a prelude to another nomad invasion that in organization and scale was to dwarf all the rest. A minor but astute tribal leader, Temujin, after twenty years of campaigns, had by 1206 united all the tribes of the faraway Mongolian steppe when in a grand council he was proclaimed Jenghiz Khan ("universal ruler").(16) By that time he had molded his horse-mounted warriors into what would prove to be the most effective mobile fighting force the world had yet seen.

In 1209 he struck outward, first south of the Gobi Desert and then east into a divided China, within six years conquering a large part of the Chinese north. By 1218 he turned west, and in response to an odious provocation from a Turkish governor in Central Asia swept across its great expanses during the next two years while leaving horrendous death and destruction in his wake. At Samarkand he divided his forces. While the larger force raided Afghanistan and northwest India, the smaller one led by his brilliant commanders Subedei and Jebe conducted a probing "reconnaissance in force" around the south end of the Caspian Sea, slashed through Georgia and crossed the Caucasus to the Crimea and almost to Kiev, mowing down every army sent against it before returning to Mongolia in 1223. Jenghiz Khan himself died four years later during another campaign in China.

His son and successor Ogedai sent forces into Persia and against the Seljuks in Turkey, and another army to exploit the weakness previously uncovered in Europe. In 1238-39 the latter force conducted the only successful winter invasion of Russia in history, conquering or coercing its principalities into long-term tribute agreements from Novgorod in the north to Kiev in the south. At Kiev the Mongol army once more divided into two forces. In 1241 the northern branch decisively defeated the combined armies of the Poles and Teutonic Knights at Legnica on the borders of Germany - while the southern force decimated the Hungarian opposition and prepared to attack Vienna. But when in 1242 news arrived that Ogedai Khan had died, the commanders turned back via Adriatic shores toward Mongolia to participate in the succession, leaving Poland and Hungary to their own devices while retaining direct control of the lower Danube lands and the Ukraine. But for this purely fortuitous event, the Mongol Empire might have reached not just to the Danube but to the Atlantic, so weak and disorganized was the remaining European opposition.

The Mongols were not finished, however. In 1243 another force defeated the Seljuk Sultanate in Turkey. Then a major offensive to secure the rest of the Near East began in 1256 led by the Mongol prince Hulegu, who started with a massive assault on the Assassins' hitherto impregnable fortress of Alamut in the Elburz Mountains, putting an end to that threat. (For 175 years Alamut had been within the Turkish domains but outside their control.) Two years later Hulegu attacked and destroyed Baghdad, captured and executed the Caliph, and massacred captives numbering an estimated one-fifth of the population, piling their 200,000 skulls into macabre pyramids. The shock to Islam was immense, and Baghdad never recovered its preeminence in the Muslim world. The Mongol sweep of the Near East was finally stopped only at Goliath's Spring in Galilee in 1260 by forces of the Mamluk Turkish sultanate of Egypt after (once again!) the main Mongol force under Hulegu withdrew to help select a new Khan.

There was one major conquest to complete, that of the Song Empire of southern China. When Kubilai (or Kublai) was named the fifth Great Khan in 1260 that became his great priority. Mongol assaults finally conquered the Song in 1279; its conquest was slower and less savage than those preceding because Kubilai wanted to win over its people rather than annihilate them, and also because its forests and intensively cultivated lands were less suited to Mongol tactics than the open grasslands of the north. With the Song capitulation the period of Mongol territorial expansion essentially came to an end except for a few relatively small gains shortly after. There were also some disastrous failures, such as Kubilai's massive seaborne attempts to conquer Japan and Java.

Kubilai was the khan that the Venetian traveler Marco Polo knew. In his account he reports having been appointed governor of Yangzhou and ruling that city for three years (population today 800,000, located 140 miles northwest of Shanghai). Marco's claim has been doubted by modern Western scholars as a boastful exaggeration of service as a minor trade official; but Professor Zhu Jiang at Yangzhou University has disagreed, saying, "Kublai needed administrators. He had recently captured southern China, the Song dynasty territory. He didn't trust the Song officials, and there were not many Mongols for those jobs. So he was using ‘colored eyes,' the foreigners."(17) (It is known that he employed as administrators thousands of foreigners, including many Persians and Arabs; Europeans were a decided novelty, probably even more attractive for that.) Kubilai's ethnic preference for responsible positions thus favored foreigners from faraway lands over the easily available but likely resentful Chinese, for good practical reasons. The Song capital, Hangzhou, which Marco Polo knew also, was then probably the world's largest city at 1.5 million.(18) (About 100 miles southwest of Shanghai, Hangzhou's population today is comparable at close to 2 million.)

By that time the empire had been divided into four khanates. Kubilai's Great Khanate (comprising China-Mongolia plus Korea and Tibet), now centered in China at his recently built capital Daidu (Beijing), had nominal suzerainty over the other three the Ilkhanate ("subordinate khanate") of the Near East; the Chagatai Khanate in Central Asia; and the Khanate of the Golden Horde covering Russia and much of present Kazakhstan. At Kubilai's death in 1294 the area of Mongol rule including vassal states(19) was by far the world's largest land empire, before or since - and contained, incredibly, a good forty percent of the entire world population.(20)

The Mongol conquests, especially in their earlier periods, were conducted mercilessly on an appalling scale. North China, Central Asia, Persia and Mesopotamia all suffered major depopulation. At the same time, the Mongols were religiously and culturally tolerant toward those subdued. Within their own ranks Buddhism, Islam, Confucianism and Christianity coexisted. (The wife of the second Great Khan Ogedai was a Nestorian Christian; she was instrumental in installing the fourth Khan, her son Mongke.) Most Mongols came to adopt the religion of the region they conquered.

After Kubilai's death Mongol supremacy began a long decline. The first to go was the Ilkhanate, in 1335. Twenty years later the Great Khanate itself split into several independent states during a period marked by Chinese peasant uprisings, and in 1368 the first emperor of the Ming Dynasty took power. The other two Mongol khanates lasted longer, but before 1400 the Chagatai Khanate of Central Asia had been mostly conquered by Timur (or "Tamerlane") of Samarkand, who was culturally Turkic though claiming descent from Jenghiz Khan, whose empire he saw himself as restoring. Timur's savagely gained empire in Central Asia, Iran, and Mesopotamia (complete with making pyramids of myriad victims' skulls from Damascus to Delhi) did not long outlast him. The Russians labored under the "Tatar yoke" the longest; but the Khanate of the Golden Horde split up in 1438 and its last remnant state was overrun by a Turkic khan in 1502, and taken over by Russia a half-century later. The impact of Mongol control, however, left indelible marks on the cultures of the lands they conquered. (Continued as Part Two)