In the beginning of the 8th century, at the time of the iconoclastic controversy, the emperor Leo the Isaurian having forced compliance to his edict against the worshipping of images, the Neapolitans, encouraged by Pope Gregory III., threw off their allegiance to the Eastern emperors, and established a republican form of government under a duke of their own appointment.
Mayer, on the other hand, denies that the Constitutum can have been forged before the news of the iconoclastic decrees of the council of Constantinople of 754 had reached Rome.
The victory of Christianity - iconoclastic in its primitive spirit - was but a single chapter in the story of decline.
He also dragged the Western clergy into the popes quarrel with the emperor at Constantinople, by summoning the council of Gentiily, at which the iconoclastic heresy was condemned (767).
The year 690 is regarded as the date of the temporary extinction of Greek in Italy, but, in the first quarters of the 8th and the 9th centuries, the iconoclastic decrees of the Byzantine emperors drove many of the Greek monks and their lay adherents to the south of Italy, and even to Rome itself.
Two incidental results of the iconoclastic movement must be noticed, the one of less, the other of more importance.
It is conjectured that the mountain was at an earlier period the abode of anchorites, whose numbers were increased by fugitives from the iconoclastic persecutions (726842).
Two years later biographical studies of Theodore Beza and Peter Martyr Vermili (Leben des Theodor de Beza and des Peter Martyr Vermili, Heidelberg, 1809) revealed more genuine scholarship. In 1812 appeared his History of the Iconoclastic Emperors of the East (Geschichte der bilderstiirmenden Kaiser des ostromischen Reichs), in which he controverted some points in Gibbon and sought to avoid painting the past in present-day colours.
In spite of his iconoclastic sympathies, he endeavoured to conciliate the image-worshippers, but incurred the wrath of the monks by entering into a second marriage with Euphrosyne, daughter of Constantine VI., who had previously taken the veil.
To the patriarchate of Constantinople, and this office he held until 815, when he accepted deposition rather than assent to the iconoclastic edict promulgated by Leo the Armenian in the previous year.