This custom of swearing by the head, or life, or safety, or genius, of the sovereign, was of the highest antiquity, both in Egypt (Genesis, xlii.

15) and Scythia.

It was soon transferred, by flattery, to the Caesars; and Tertullian complains, that it was the only oath which the Romans of his time affected to reverence.

See an elegant Dissertation of the Abbe Mossieu on the Oaths of the Ancients, in the Mem de l'Academie des Inscriptions, tom.i.

p.
208, 209.] While the emperor and his court enjoyed, with sullen pride, the security of the marches and fortifications of Ravenna, they abandoned Rome, almost without defence, to the resentment of Alaric.