The
history of the Roman Empire covers the history of
Ancient Rome from the fall of the
Roman Republic in 27 BC until the abdication of the last Emperor in 476 AD. Rome had begun expanding shortly after the founding of the Republic in the 6th century BC, though didn't expand outside of
Italy until the 3rd century BC. Civil war engulfed the Roman state in the mid 1st century BC, first between
Julius Caesar and
Pompey, and finally between
Octavian and
Mark Antony. Antony was defeated at the
Battle of Actium in 31 BC. In 27 BC the
Senate and People of Rome made Octavian
imperator ("commander") thus beginning the
Principate (the first epoch of Roman imperial history, usually dated from 27 BC to 284 AD), and gave him the name Augustus ("the venerated"). The success of Augustus in establishing principles of dynastic succession was limited by his outliving a number of talented potential heirs: the
Julio-Claudian dynasty lasted for four more emperors—
Tiberius,
Caligula,
Claudius, and
Nero—before it yielded in 69 AD to the strife-torn
Year of Four Emperors, from which
Vespasian emerged as victor. Vespasian became the founder of the brief
Flavian dynasty, to be followed by the
Nerva–Antonine dynasty which produced the "
Five Good Emperors":
Nerva,
Trajan,
Hadrian,
Antoninus Pius and the philosophically inclined
Marcus Aurelius. In the view of the Greek historian
Dio Cassius, a contemporary observer, the accession of the emperor
Commodus in 180 AD marked the descent "from a kingdom of gold to one of rust and iron"—a famous comment which has led some historians, notably
Edward Gibbon, to take Commodus' reign as the beginning of the
decline of the Roman Empire.