Zosimus, 1. v. [c. 47-49] p. 367, 368, 369. 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 Massieu on the Oaths of the Ancients, in the Mem. de l'Academie des Inscriptions, tom. i. p. 208, 209.