See Anastasius (p. 199) and Eginhard (c.xxviii. p. 124 - 128.). The unction is mentioned by Theophanes(p. 399), the oath by Sigonius (from the Ordo Romanus), and the Pope's adoration more antiquorum principum, by the Annales Bertiniani (Script. Murator. tom. ii. pars ii. p. 505.).