Back in the days when our ancestors still dressed in skins and hides and had just given up stone weapons for bronze, a group of people moved out of central Europe to the north of Italy. They stayed there for a thousand years, made pottery and grew beans, beets, barley, and millet and finally learned how to use iron. They also grazed cattle and herded sheep, and so one day when they learned that the coastland from the Tiber River to the Bay of Naples was so lush with tall green grass that it was called Vitelia (the name Italy comes from mispronouncing this), or Calfland, they moved south again.

There they settled in the rugged blue hills, and there they became the various Italian tribes. Most important of these to our story were the Latins. For reasons of safety, these Latins, like the others, lived in the craggiest places they could find, but they always came down to the campania, as the level land was called, to fatten their lowing herds. And in 754 B.C., according to Roman legend, twin brothers, Romulus and Remus, decided to stay there. They became chieftains of a band of robber cattle-herders, and at the exact spot where the twins said they had been nourished as babes by a she-wolf (who some say was a woman named Lupa, the Latin word for “wolf”), they founded a small town of mud-and-wattle houses.

They named it Rome after Romulus, the older twin. Little did anyone dream that one day it would be one of the most famous cities in the world! Still less did anyone imagine that the Romans would march out of it to conquer the world!

But that is just exactly what they did. In the beginning, they had troubles and trials. In fact, an old story says that when the Gauls from France invaded the city, the capital was saved only when a gaggle of geese cackled and warned the senators.

But the Romans were stubborn, good fighters, well-disciplined, and no matter how bitterly they battled each other in more than one bloody civil war, they always stood together when they faced an enemy. By the time of Julius Caesar 700 years later, they had reached the English Channel in one direction and the Caspian Sea in the other. When Trajan was emperor (about 100 A.D.), practically every part of the known civilized world was included in their empire. Of the eighty-two countries in the United Nations at the time this book was written, all or a part of at least thirty were in Trajan’s empire, and a great majority of the other fifty-two countries are in lands, like America, that hadn’t been discovered. They were ruled by one man.

What is more, soon all the inhabitants of all these lands were Roman citizens. Civis Romanus sum. I am a Roman citizen. This could be said by longhaired Celts walking the heather in Britain; by Berbers in the Atlas Mountains in Africa; by haughty Spaniards (Trajan himself was born in Spain); by Gauls in France, Egyptians, Greeks, Syrians, Arabs; even by Scythians and Sarmatians from South Russia, and by Germans from across the Rhine.

This was a great achievement that had never happened before, but it also made a lot of difficulties.

Take size alone. The Roman Empire was now too big to manage. In those days, you couldn’t fly a general (or a tax collector, or an imperial officer, or the emperor himself) from York, England—that’s where Constantine the Great was when he started toward Rome to become the Roman emperor—to the Persian border in a matter of hours. You couldn’t even put him on a fast train. The Roman roads were famous, but the only way you could travel them was on foot, on horseback, or in a litter or chariot. And from one end of the empire to the other was 3,000 miles!

Two centuries after Trajan, an emperor called Diocletian decided to do something about it. Diocletian was the son of a freed slave, but he became the first absolute ruler the Roman Empire ever had. Before that the emperor was merely princeps (from which the English word “prince” is derived), or first citizen. But once Diocletian had all this power, he proceeded to divide it up. He appointed a co-emperor (a second Augustus) with an assistant emperor called a caesar to help him, and put him in charge of the Roman Empire in the West. Diocletian himself, with his own caesar, kept the East. Although he was still head emperor and the other emperor was supposed to obey him, the Roman Empire was now divided into two parts.

About forty years later, another emperor took an even more important step. Constantine the Great decided that the empire needed a second capital as much as it needed two rulers, and since he was a Christian emperor—actually he was the first Christian emperor—he decided it must be a Christian city.