THE LACK OF PRIMOGENITURE AND THE FALL OF ROME. In Mary Beard’s review in the London Review of Books (April 26) of CALIGULA: A BIOGRAPHY by Aloys Winterling, she says that Augustus failed to create a reliable system of monarchical succession, in part because Rome did not have a system of inheritance such as primogeniture. I posted here about Adrian Goldsworthy’s theory that Rome fell because emperors were preoccupied with attempts on their lives; Goldsworthy says that starting from 180 A.D. every adult emperor faced at least one attempt to depose him. Mary Beard says that there are claims that every member of the first dynasty of Roman emperors was murdered. I can explain the quiet period in the middle as being primarily the period when each emperor adopted as a son his chosen successor. When Marcus Aurelius, the last of the Five Good Emperors, died in 180 A.D. he returned to the hereditary principle of naming his genetic son as his successor, and the bloody battles for succession began again.
Mary Beard also ventures an explanation for why the Roman historians portray emperors as monsters. If an emperor has been killed in a coup, men who were courtiers in the old regime may curry favor with the successor by speaking ill of the previous emperor. And those contemporary histories are the basis for modern histories.