The Roman empire consisted of the lands surrounding the Mediterranean Sea and beyond that were under Roman rule from the end of the 500 year old Roman Republic, at the end the first Century BC, to AD1453 when Constantinople was finally overrun by the the advancing Turkish Empire. Initially controlled from Rome, in AD285 the Empire was split into two halves: a Western empire ruled from Rome and an Eastern empire ruled from Constantinople; after which the Western empire fell into steady decline due mainly to incursions by northern tribes and internal disputes between various claimants for the title of Emperor. The Eastern Empire continued on, occasionally re-conquering lands in the west, until its final collapse in AD1453.
Latin and Greek
Rome, Constantinople (E), Milan (W), Ravenna (W)
27BC - Augustus proclaimed Augustus
AD285 - Empire split into Eastern and Western halves
AD330 - Constantinople as capitol of the empire.
AD1453 - Constantinople is captured by the Turks
Over 80 million at its maximum
The Roman Empire was ruled by an Emperor. The first one was Octavian, the adopted son of Julius Caesar. When he became Princeps (Emperor) meaning first amongst equals he used the name Augustus. At first there was a definite succession of the line of Augustus but there were times when there were more than one Emperor as different contenders (usually Generals) fought over the title. The list below records the most prominent person to be Emperor around the dates. In practice there could be as many as four at the same time, especially towards the end when the Empire was too big to be governed by one man.
Claudius II Gothicus
Theodosius I the Great
Octavian was the adopted son of Julius Caesar. He is probably the most important person in the history of the Roman Empire. When Julius Caesar was assassinated the Republic was in disarray. Julius Caesar effectively had become king, something that the leaders of the Republic abhorred, and it cost him his life. The Republic was ruled by a Senate of annually elected but had no formal constitution; the law was defined by tradition, precedent and the consensus of the Senate. This system was the cause of the problems in the Republic as politicians set dangerous precedents for their own advantage and started to use violence and intimidation to get their own way. This was effectively how Caesar gained his dominant position of dictator in the Senate. Caesar made no attempt at sorting out the system of government. Caesar's will named his adopted son Octavian, the grandson of his sister Julia, as his heir.
On Caesar's death there was a power struggle as several factions tried to gain the position of power that Caesar had left. Octavian, adding Caesar to his name, was amongst these factions, along with other, mutually antagonistic, powerful people like Mark Anthony, Caesar's friend, and Brutus, one of Caesar's assassins. In 30BC Octavian, a shrewd politician and able leader, emerged from the turmoil as the sole leader and saviour of the Roman Republic.
The Republic style of government had failed and Octavian recognised this. He also recognised the dangers of being perceived as a king, the mistake Julius Caesar had made. Octavian set about consolidating his rule by legal means, but he was also careful to respect tradition. Octavian took the title Augustus a term that had religious and social meaning but not one that suggested political supremacy. His titles were never accepted on a lifetime basis, they were all for a given period of 5 years or so. In this way he created the illusion that he didn't want absolute authority whilst patiently acquiring it. This assured that the aristocracy would not feel threatened and turn on him as they did Julius Caesar.