History of the Roman Empire disputes about the supreme authority, this finally formalised a peaceful succession of the emperor: in each half a "Caesar" would rise up to replace the "Augustus" and select a new "Caesar". On May 1, 305, Diocletian and Maximian abdicated in favour of their "Caesars". Galerius named the two new "Caesars": his nephew Maximinus for himself, and Flavius Valerius Severus for Constantius. The arrangement worked well under Diocletian and Maximian and shortly thereafter. The internal tensions within the Roman government were less acute than they had been. In "The Decline and Fall of the Roman Empire", Edward Gibbon notes that this
Historiography of the fall of the Western Roman Empire the cities, which became overpopulated. Roman cities were only designed to hold a certain number of people, and once they passed that, disease, water shortage and food shortage became common. Publishing several articles in the 1960s, the sociologist Seabury Colum Gilfillan advanced the argument that lead poisoning was a significant factor in the decline of the Roman Empire. Later, a posthumously published book elaborated on Gilfillan's work on this topic. Jerome Nriagu, a geochemist, argued in a 1983 book that "lead poisoning contributed to the decline of the Roman empire." His work centred on the level to which the ancient