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
Fall of the Western Roman Empire of Commodus, after a number of introductory chapters. Arnold J. Toynbee and James Burke argue that the entire Imperial era was one of steady decay of institutions founded in republican times, while Theodor Mommsen excluded the imperial period from his Nobel Prize-winning "History of Rome" (1854–56). As one convenient marker for the end, 476 has been used since Gibbon, but other key dates for the fall of the Roman Empire in the West include the Crisis of the Third Century, the Crossing of the Rhine in 406 (or 405), the sack of Rome in 410, and the death of Julius