From the councils, and historians Cedrenus, Evagrius, Theophanes, &c.
See Baronius, Henschenius. t. 3, Feb. p. 71. Fleury, l. 27, 28. Quesnel,
in his edition of the works of St. Leo, t. 2, diss. 1, and F. Cacciari,
t. 3, Exercit. in opera St. Leonis, Romae, an. 1755. Dissert. 4, de
Eutychiana Haer. l. 1, c. 2, p. 322; c. 8, p. 383; c. 9, p. 393, c. 11,
p. 432.