History of the Roman Empire 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. In 212, during the reign of Caracalla, Roman citizenship was granted
Historiography of the fall of the Western Roman Empire and enjoy periods of recovery and cultural brilliance, but its size would remain a fraction of what it had been in classical times. It became an essentially regional power, centered on Greece and Anatolia. Modern historians tend to prefer the term "Byzantine Empire" for the eastern, medieval stage of the Roman Empire. The decline of the Western Roman Empire was a process spanning many centuries; there is no consensus when it might have begun but many dates and time lines have been proposed by historians. The various theories and explanations for the fall of the Roman Empire in the West