In this section, you should learn the meaning and significance of the following
This seemed like a pretty good deal for the new Iron-Age Empires, since they had a greater population than the peoples of the North, and so could assemble much larger armies. They expanded to absorbed regions much unlike their homeland and then spent a great deal of time and energy in developing institutions and traditions to unify the different peoples under their control. By about 200 BC, these Classical Empires were flourishing and were creating arts and literatures of great beauty while at the same time maintaining states in which law, order, security, and prosperity characterized the inhabitants way of life.
Then, in the 300's AD, those people from Inner Asia came once again, this time riding horses and shooting at the foot soldiers of the Classical Empires with short but powerful bows. They attacked all of the empires from China to Rome, and succeeded, at least for a time, in conquering and ruling a sizable portion of each of them. We'll concentrate our attention on Rome, since something happened (or, rather, something didn't happen) there that would make a great deal of difference in the future.
The Roman empire was centered on the basins of the eastern and western Mediterranean Sea, although it had extended its power to include most of continental Europe up to the Rhine and Danube rivers. Although it had begun as a city-state and a republic, it had become a empire in about 30 BC and power had been concentrated in the hands of an emperor who, like the emperors of the other Classical Empires, was considered to be at least semi-divine if not completely so. When the Roman empire emerged, however, it was missing one important thing. There was no provision for how power was to pass from a dead ruler to his successor. Over time, various methods were tried, usually being imposed by violence of one sort or another. At the same time, the Romans found that they had to invest a lot of their resources in building fortifications to defend the western portions of their frontier against various tribes of people, all speaking variations of old German and so called Germanic barbarians. They were not really barbarians except from the Roman point of view, but that's how the Romans described them, and the description has more or less stuck. On their eastern frontier, the Romans found themselves engaged in a long and costly series of wars with the New Persian Empire, wars which weakened the Romans a great deal and gained them very little.
By about 275 AD, the Roman empire had disintegrated almost completely, and there were thirty different men each with an army and each claiming to be emperor. It was clear that, if the empire was to survive internal collapse, changes had to be made. In 383, a general by the name of Diocletian managed to defeat other claimants and restore the empire to a single rule. He began a series of reforms that were really completed and made effective by his successor Constantine the Great (306-337). Their reforms changed the Roman empire greatly.
In the first place, they were unable to continue the investment necessary to maintain the unity of the eastern and western halves of the empire, and so divided the empire into two parts. The western section was far less developed and well-populated than the eastern portion of the old empire, so it was necessary to increase taxes there. The result of this was the disappearance of the middle class and the flight of independent farmers to the protection of their wealthy (and tax-exempt) noble neighbors. The West slowly sank while the East, freed of the expense of maintaining the West, soon began to flourish. The old state religion hadn't seemed to work very well in keeping people peaceful and loyal to the central government, so Constantine, for reasons best known to himself, chose to make a mystical eastern cult known as Christianity the state religion. It took a long time for these reforms to take hold, but, by 400, the empire was a far different place than it had been.
While all of this was going on, things were happening in Inner Asia. We are not sure what caused the movement of peoples, but the nomads on horse-back seemed to be expanding in all directions. In China, the empire had been divided into northern and southern empires, and, in 386, the northern empire was taken over by peoples from Inner Asia, speaking the Mongol language. In India, the White Huns occupied the western part of the country in about 425, and, for a long time, carried out destructive raids from this base into northern India. Another branch of the White Huns gained control of an eastern portion of the Persian empire in about 460.
The situation in the Roman empire(s) was a bit more complicated. When the Huns had reached them, one of the German tribes asked the eastern emperor for permission to enter the empire and take refuge behind the Danube River. He agreed, and they crossed over and took up Roman lands. They had not expected to have to pay taxes, however, and decided to march to the eastern Roman capital at Constantinople and complain to the emperor. The emperor decided that the Germans needed to be taught a lesson and so led his entire army against them. Much to everyone's surprise (including the Germans'), the Germans defeated the Romans, killing the emperor and practically wiping out the imperial army (378). It took a while to get things back in order, but the new eastern emperor decided that it would be a much better idea for the Germans to attack the western empire. He was able to offer them gold and silver and so, in 407, the Germanic tribes began pouring across the western frontiers of the empire. By 500, German kings ruled all portions of the western empire, although they all had legal documents proving that they were actually representatives of the emperor in Constantinople, who had employed them to re-unit the empire under his dominion.
The sixth century was a period during which the Classical Empires recovered the territories that had been lost. In a long and complex process, China was finally reunited in 589 and, in 618, the great T'ang dynasty (589-907) was established. The power of the White Huns in India was ended with their defeat by the Turks in their homeland, while the Persians and Turks allied to drive the White Huns from the Persian territory they had occupied.
Something strange happened in the area of the Mediterranean. The emperor Justinian (527-565) undertook the reconquest of the western empire from its German rulers and made considerable headway in this before his death. After his death, however, his successors busied themselves fighting against the Persians and the inhabitants of the eastern empire seemed to have little desire to hold onto a western empire that was simply a drag on the eastern economy. They instead abandoned many Roman institutions, returned to their native Greek tongue, and allowed a new wave of Germanic invaders to occupy what had once been the Roman Empire in the West. Although the inhabitants of the eastern Mediterranean continued to refer to themselves as Romans, the changes in that portion of the Roman Empire were so great, that historians generally refer to it as the Byzantine Empire. The Byzantine Empire and its great capital of Constantinople survived until its final conquest by the Turks in 1453.
Western Europe was at the end of the great belt of civilizations and was cut off from the advances those civilizations made in later years. Such things as paper, printing, gunpowder, the compass, windmills, and many other innovations, reached Europe only after they had been common for many years in the rest of the civilized world. What is more, Western Europe was the only portion of a Classical Civilization to fall to "barbarian" invaders and not to be recovered. It had to create a new tradition acceptable to the disparate people who inhabited the region. The Germanic inhabitants had no tradition of centralized rule and there was no central geographic feature (such as a great river basin) upon which to base such a centralized rule. Although the ideal of a Roman Empire of the West remained attractive for a long time, the Europeans began to adapt the traditions and culture of a Classical Empire to an essentially decentralized and egalitarian society.
The Roman Empire is a very popular topic. There are over 1500 web sites devoted to aspects of the subject, so it is very difficult to chose one or two to give you an overview. A small selection of sites concentration on the late empire will have to serve as a sample. The ORB encyclopaedia has an Overview of Late Antiquity, and the ruins of Diocletian's palace is quite evocative. Another site, providing a history of The Early Centuries of the Greek Roman East will have to round out that subject of the Late Roman Empire, a topic that merges into that of Medieval Europe.
This might be a good opportunity to get a better picture of the Roman Empire at its height. For pure visual effect, the Pompeii Forum Project is well worth the time it takes to load it. There is a nice site showing a reconstructed Roman villa, or country estate, in Germany, and another that features the reconstruction of the frontier town of Xanten, also in Germany. There is also the Vichten mosaic, found in modern Luxembourg, that illustrates as well as anything the amalgamation of Roman and Greek themes into Graeco-Roman culture. For a change of pace, you might wish to see the sights of an ancient Qin Palace in China. This last site is actually a catalogue, but the pictures of the works for sale are quite beautiful, and the text is intriguing.