The term adoptive emperor (AE) is applied to the emperors from Nerva to Marcus Aurelius because they each adopted their respective successor. The special characteristic was that the successor supposedly came from outside the family: sed Augustus in domo successorem quaesivit, ego in re publica ( Galba in his speech at the adoption of L. Calpurnius Piso Frugi, Tac. Hist. 1,15,2). Among the Julio-Claudian dynasty, Rome was supposed to have been unius familiae quasi hereditas. The reason why the successor, per adoptionem, should be the ideal form of rulership…