The Roman Empire was the largest empire of the ancient world. Its capital was Rome, and its empire was based in the Mediterranean. The Empire dates from 27 BC, when Octavian became the Emperor, or Augustus, until it fell in 476 AD, marking the end of the Ancient World and the beginning of the Middle Ages, or Dark Ages.

The empire was the third stage of Ancient Rome. Rome was first ruled by Roman kings, then by the Roman Republic, then by an emperor.

Augustus Caesar ruled the Roman Republic and Roman Empire so Rome was a republic before it was an empire.

Tiberius Caesar ruled Rome as also and appointed Pontius Pilate.

Many modern lands were once part of the Roman Empire, for example Britain (not Scotland), Spain, Portugal, France,  Italy, Greece, Turkey, Germany, Egypt, Levant, Crimea, Switzerland, and the north coast of Africa. The main language of the Roman Empire was Latin with Greek as an important secondary language, especially in the Eastern provinces of the Empire. 

The western half of the Roman Empire lasted for about 500 years till the barbarian general Odoacer defeated its final emperor Romulus Augustus. On the other hand, the eastern half, consisting of the Balkans, Anatolia, The Levant and Egypt, continued for about a thousand years more (the Levant and Egypt were lost to the Arabs in the 8th century). The eastern part was called the Byzantine Empire. Its capital was Constantinople, now called Istanbul.

Governing the Empire 
In order to control their large empire, the Romans developed ideas about law and government. They developed the best army in the world at that time, and ruled by force. They had fine engineering, and built roads, cities, and outstanding buildings. The Empire was divided into provinces, each with a governor plus civil and military support. Letters, both official and private, went constantly to and from Rome.

Trade was most important for Rome, a city of more than a million people, by far the largest city in the world. They needed, and got, wheat from Egypt, tin from Britannia, grapes from Gaul, and so on. In return, the Romans built provincial capitals into fine cities, protected them from raids by barbarians, and provided education and career opportunities for young people in the provinces, such as jobs in the Roman Army.

In principle, emperors had absolute control, and could do as they pleased. In practice, they faced some difficult problems. They had a staff of what we call 'civil servants' and the advice of the Roman Senate. The emperor had to decide what were the most important issues facing the Empire, and what should be done about them. Most of them tried to do two things. One was to do things to improve the life of Romans in peacetime. The other was to fight and defeat Rome's enemies. A wealthy empire always has enemies.

With kings and emperors, a big problem is the order of succession. Kings were sometimes followed by their eldest son, if he was capable of ruling. For Roman emperors, more often it would be an adopted son. It worked like this. The emperor would notice an outstanding young man from one of the best families. He would adopt him as his son. Before he died he would make clear whom he thought should succeed him, by making him a Roman consul, or by stating in his will that the younger man should succeed him. Sometimes this worked; sometimes it did not. Every now and then there would be a civil war between claimants to the throne.

An adopted son or two gave the emperor more choices. Some emperors had no son; some had sons who did not survive. Later on, emperors grew so weak that the Roman army would just pick one of their generals to be the next emperor. This often led to civil war. The life stories of the emperors can be found in List of Roman emperors.

The Romans fought many wars against other countries, and against barbarians several times.  They enjoyed watching violent sports. They enjoyed watching chariots races, and fights between gladiators (men using weapons). Unlike in modern sports, the fighters were often killed in fights. Romans enjoyed these shows in the Colosseum.

The Romans had great civil engineering. They built many large public buildings and villas, aqueducts to carry water, stone bridges and roads. Some of these things can still be seen today. Many famous writers were Romans, including Cicero and Virgil. 

The New Testament of the Bible tells about the Romans in the life of Jesus Christ. During Jesus' life, the Romans, who were pagans, ruled his country. Later, several emperors tried to destroy Christianity but they did not succeed. By 312  the emperor Galerius allowed people freedom to follow Christianity, and the next year, a general, Constantine, became emperor and converted to Christianity.

The city of Rome was taken over several times by barbarians, notably in 410  when the Goths sacked the city (looting). The last Western Roman emperor, Romulus Augustus, resigned in 476 . The Roman Empire would last another 1,000 years as the Byzantine Empire in the east.

The main coin of the Roman Empire was the silver denarius. Later denarii were smaller.

Various reasons have been given for the fall of Rome. Edward Gibbon wrote The Decline and Fall of the Roman Empire in which he investigated various ideas. Chief among them was (in his opinion) was the effect of Christianity on the ability of the Empire to defend itself militarily.

Other historians blame the unstable system of leadership. In a 50-year period, only 2 out of 22 emperors died a natural death. Most of the emperors were assassinated.

References

Other websites 

 An old map of the Roman Empire in 400 AD
 BBC, Romans for Children , website on ancient Rome for children at the level of primary school
 Rome Unleashed, interactive educational website on ancient Rome for students