Tacitus,The Annals, xv 48,The Histories, i. 15. In the former of these passages we may venture to change paterna into materna. In every generation from Augustus to Alexander Severus, one or more Pisos appear as consuls. A Piso was deemed worthy of the throne by Augustus (Tacitus,The Annals, i. 13.). A second headed a formidable conspiracy against Nero; and a third was adopted, and declared Caesar by Galba.