For the promotion of Gallus see Idatius, Zosimus, and the two Victors. According to Philostorgius (1. iv. c. 1 ), Theophilus, an Arian bishop, was the witness, and, as it were, the guarantee of this solemn engagement. He supported that character with generous firmness; but M. de Tillemont (Hist. des Empereurs, tom. iv. p. 1 1 20) thinks it very improbable that a heretic should have possessed such virtue.